8 Step Problem Solving Method - University of Kentucky

8 Step Problem Solving Method

• Deepen your awareness of the importance of the 8 step process to effective problem solving • Apply the process to your own work situation during class discussion • Experience how the A-3 tool communicates the process thinking • Apply in the work environment that will work both in the field and in the on-campus lab

Learning Goals 2

8 Step Problem Solving Process 8 Step Process for Problem Solving Steps Depth Zero level Go deeply on each step Complete

Step 1

Step 2

Step 3

Step 4 Root Cause

Step 5

Step 6

Step 7

Step 8 Toyota strength‐ standardize

3

1

Be adaptable to the work process needs-- take action quickly If necessary, use TEMPORARY measures -when a problem occurs, take action quickly

Keep at it until TRUE countermeasures are in place -that which if implemented prevents problem from returning

Speedy Action in a Timely Manner 4

Difference between “Temporary Measure" and “Countermeasures”

Problem

Why?

Machine over travels

Limit switch not activated (Fact)

Why ? Limit switch Arm is Frozen (fact)

(Temporary

measure) Replace the limit switch

Prevents the recurrence

Why?

Root Cause

Limit switch is in Coolant air flow

(Countermeasure) shield limit switch from coolant

Temporary Measure Example 5

Action to stop or contain the problem-can add necessary extra work to the process. ( + $ / + / +  ) • When a problem occurs, take action quickly • Purpose is to contain the problem, not solve it.

Temporary Measure 6

2

Select the optimal containment action on the following criteria: • Simplicity • Minimal modification to current process • Time to implement Option 1 Simplicity Modification Time

10 9 10 29

Option 2

Option 3

8 7 10 5 9 7 27 17 Sum the score and select the option with the highest score

Rate each option relative to each other for each criteria

Short-Term Containment

7

Problem Identified C/M Identified C/M Implemented Follow up Complete

Temporary Measure Implementation Plan 8

A problem is … The current situation gap to the standard = PROBLEM • Fact based • Discovery driven Standard Gap = Problem Current Situation

What Defines a problem in the 8 Step method? 9

3

Non Value Added Work = Waste • Waste is any factor which does not contribute to the process by adding value. • The goal of Lean is to eliminate any factors which raise cost without adding value to the product.

What Defines a problem in the 8 Step Method? 10

Motion

Overproduction

Inventory Quality Defects

The 7 Wastes!

Waiting

Over Processing

Transportation


Would you like to work in this place?


4

See normal vs abnormal

After Racks and Containers for Small Lot

SOP

Andon Cord Andon Board Information Charts

Scoreboard 5-S

Safety Glasses On

Foot-printing Floor

Walking Aisle Ergo Aid Table

13 What Defines a problem in the 8 Step Method?

Step1.Clarify the Problem Step 2. Break Down the Problem

P

Step 3. Target Setting

Step 4. Root Cause Analysis Step 5. Develop Countermeasures

D

Step 6. See Countermeasures Through

C

Step 7. Monitor Both Results and Processes

A

Step 8. Standardize Successful Processes

8 Step Process for Problem Solving 14

• See handout

Example of Problem A-3 Report 15

5

Proceedings

8 Steps

Step 1. Clarify the Problem

(1) Clarify the “Ultimate Goal” of your responsibilities & work (2) Clarify the “Standard” of your work (3) Clarify the “Current Situation” of your work (4) Visualize the gap between the “Current Situation” and the “Standard”

Step 1 - Clarify the Problem 16

Visualize the gap between the “Current Situation” and the “Standard”

Defects

Problem The Standard

.5 .4 .3

The Current Situation

.2

Visualize the gap between the current situation and the standard

.1

Aug

Sep

Oct

Nov


Process1. Clarify the “Ultimate Goal” of your responsibilities & work

Ultimate Goal

My job’s purpose

My work & Responsibilities

To provide customers with highly functional and high-quality cars at reasonable prices in a timely manner

To meet customer demand

To meet Production Plans


6

1. Clarify the Problem Ultimate Goal: Assure TMMK cars meet customer requirement for quality Standard:

Zero audit defects from sealer area

Current Situation:

7 water leaks on 7/28 15 10

7

Gap=7 0

5

Example: Step 1

0 Actual

Standard

19

1. Clarify the Problem Ultimate Goal: TMs are compensated for work completed and paid timely and fairly Standard: 100% (3300) of TM’s paychecks are deposited error free Current Situation: 80% (2640) of TM’s paychecks are deposited error free

GAP 20% (600) paychecks Need a manual check To correct errors

100 80 60 40 20 0

3300

2640 Gap=(20%) 660

80%

100%

Current Standard

Example: Step 1 20

8 Steps Step 1. Clarify the problem

Step 2. Break down the problem

Proceedings (1) Clarify the “Ultimate Goal” of your responsibilities & work (2) Clarify the “Standard” of your work (3) Clarify the “Current Situation” of your work (4) Visualize the gap between the “Current Situation” and the “Standard”

(1) Break down the problem (2) Identify the prioritized problem (3) Specify the point of occurrence by checking the process through GENCHI GENBUTSU

Step 2 - Break Down the Problem 21

7

Big Problem

Problem

Problem

What Where When Who

Problem

NOT Why! Problem

Problem

Problem

Problem

Problem

Problem

Problem

Prioritized Problem

Prioritized Problem at the Point of Occurrence


• Formulating a clear, concise statement from your Gap • The statement describes the difference between the standard and current situation • During this step, break the large problem into smaller, more specific problems • If you can’t describe it, you can’t solve it!

Step 2: Break Down the Problem 23

Narrow the problem sufficiently Classify and quantify 7 Water leaks

1 on Avalon

1 in Mohican

6 on Camry

Vehicle Type

1 side

Process

5 Tail light

Many water leaks in the tail light

Prioritized Problem

Priority decision: tackle the biggest impact problem FIRST


8

3% increase in SCRATCHES found on vehicle at Final Inspection

Classify Then Quantify

Trunk=0% Trunk Left=95% Roof=0% Left Roof Right=5% Hood=0% Right Hood

Frt Door= 80%

RR Door= 15%

Fender=0%

Qtr Pnl= 5%

80% Window Frame

Prioritized Problem

15% Door Handle

5 % Side Pnl


• The point of occurrence (POO) is the actual work element at the physical location where the problem is first seen • For example, walk the line back. Check each work station, until you arrive at the station where the problem is no longer seen 8 Step Problem Solving (Locate Point of Occurrence)

26

Standard Work Pick seat from back w/carrier

Set seat to car

Align seat to rail

Remove carrier

Shoot bolts

(POO) Defect was found here

Process steps

Scuffed / Damaged Cup Holder @ CSA

Scuffed / Damaged Cup Holder @ start of final

Scuffed / Damaged Cup Holder @ after Front seat install

No damage @ before Front seat install

Back track

Locate Point of Occurrence (POO) 27

9

Where is Point of Occurrence? Prioritized Problem at the Point of Occurrence

Why is Point of Occurrence important?

For efficient use of time & effort


2. Break Down the Problem 7 Water leaks

1 on Avalon

1 in Mohican

6 on Camry

Vehicle Type

1 side

Process

5 Tail light Many water leaks in the tail light

Go and See Investigation for Point of Occurrence 1) Floor Brush--Finish lower seam on end panel Prioritized Problem

2) Engine Room Finish--Finsh the area just above and below the tail light Processes

Standard Work

1st Application

Engine Room

Finish Hood Corner

Trunk Brush

Floor Brush

Finish Rear Hood

Finish Mirror Plate

Finish Upper end panel

2nd Application

Finish Side tail light

Example: Step 2

Engine Room Finish

Point of Occurrence (POO)

Finish below tail light

Point of Occurrence

29

2. Break Down the Problem 20% (660/3300) manual checks being issued

Group Leader Error 35% (231/660)

Time Execution 61% (142/231)

Other 23% (151/660)

Other 39% (90/231)

Salary Continuation 42% (277/660)

STD Not Paid 30% (83/277)

FMLA PTO Not Paid 70% (193/277) Prioritized Problem

FMLA Process Flow

T/M obtains FMLA form

Point of Occurrence (POO)

T/M submits form to TMR by deadline

TMR reviews form - submits by deadline

Payroll system updated by deadline

T/M received paycheck with correct amount

Problem: FMLA paperwork is not received from TMR by the payroll deadline.

Example: Step 2 30

10



Step 3. Set a target

Proceedings (1) Clarify the “Ultimate Goal” of your responsibilities & work (2) Clarify the “Standard” of your work (3) Clarify the “Current Situation” of your work (4) Visualize the gap between the “Current Situation” and the “Standard” (1) Break down the problem (2) Identify the prioritized problem (3) Specify the point of occurrence by checking the process through GENCHI GENBUTSU

(1) Make a commitment (2) Set measurable, concrete and challenging targets

Step 3) Set a Target 31

Prioritized Problem Standard Problem

Big Problem Current Situation

Point of Occurrence

Target

Problem

Problem

Step 3 - Set a Target 32

3. Target Setting Target: Eliminate 5 tail light area water leaks on Camry by 7/29

Example: Step 3 33

11

3. Target Setting Target: Eliminate 100% late submissions of FMLA forms to meet payroll deadline by arch 2009. (193 of 660 total gap)

Example: Step 3 34

Example through Steps 1, 2, & 3 1. Clarify the Problem Ultimate Goal:

No waterleaks in TMMK produced cars

Ideal Situation (Standard):

Zero audit defects from Sealer area 15

Current Situation:

7 waterleaks on 7/28

10

7

5

Gap = 7 Goal

Actual

2. Break Down the Problem 7 Water leaks

1 on Avalon

6 on Camry

1 in Mohican

5 Tail light

Vehicle Type

Process

1 side


Prioritized Problem

Go and See Investigation for Point of Occurrence 1) Floor Brush--Finish lower seam on end panel 2) Engine Room Finish--Finsh the area just above and below the tail light 1st Application

Engine Room

Floor Brush

Trunk Brush

2nd Application

Finish Hood Corner

Finish Rear Hood

Finish Mirror Plate



Engine Room Finish


Point of Occurrence

3 5

3. Target Setting Target: Eliminate 5 tail light area water leaks on Camry by 7/29

3 1. Clarify the Problem Ultimate Goal: TMs are compensated for work completed and paid timely and fairly

3300

100 80 60 40 20 0

Standard: 100% (3300) of TM’s paychecks are deposited error free Current Situation: 80% (2640) of TM’s paychecks are deposited error free

2640 80%

Gap=(20%) 660 100%

Current Standard 2. Break Down the Problem 20% (660/3300) manual checks being issued

Group Leader Error 35% (231/660) Time Execution 61% (142/231)

Other 39% (90/231)

FMLA Process Flow T/M obtains FMLA form

T/M submits form to TMR by deadline

Other 23% (151/660)

Salary Continuation 42% (277/660) STD Not Paid 30% (83/277)

FMLA PTO Not Paid 70% (193/277) Prioritized Problem Point of Occurrence (POO) T/M received TMR reviews Payroll system paycheck with form - submits updated by correct amount by deadline deadline

Problem: FMLA paperwork is not received from TMR by the payroll deadline. 3. Target Setting

Target: Eliminate 100% late submissions of FMLA forms to meet payroll deadline by March 2009. (193 of 660 total gap) 36

12

Example through Steps 1, 2, & 3

37




Step 4. Analyze the Root Cause

Proceedings (1) Clarify the “Ultimate Goal” of your responsibilities & work (2) Clarify the “Standard” of your work (3) Clarify the “Current Situation” of your work (4) Visualize the gap between the “Current Situation” and the “Standard” (1) Break down the problem (2) Identify the prioritized problem Specify the point of occurrence by checking the process through GENCHI (1)(3) Make a commitment GENBUTSU (2) Set measurable, concrete and challenging targets

1) Examine the Point of Occurrence and think of possible causes without prejudice (2) Gather facts through GENCHI GENBUTSU and keep asking “Why?” (3) Specify the root cause

Step 4 - Analyze the Root Cause 38

Time for WHY

Prioritized Problem at the Point of Occurrence

Possible cause

Possible cause

Possible cause

Possible cause

Not a fact

Not a fact

Not a fact

Fact

Possible cause

Possible cause

Possible cause

Not a fact

Not a fact

Fact

Possible cause

Not a fact

Think of all meaningful possible causes

Go and See to confirm

Possible cause

Repeat

Fact

Root cause

Step 4) Analyze the Root Cause 39

13

(Example) Bad polishing of painted parts Man (Human): Standard work being followed? Machine: RPMs correct? Material: Correct compound? Method: Polishing standard correct? Environment: Work place temperature correct?


Example:

Welding robot stops in the middle of its operation.

Why? A fuse in the robot has blown. Why? Circuit overloaded. Why? The bearings have damaged one another and locked up. Why? There was insufficient lubrication on the bearings. Why? Oil pump on robot is not circulating suffi Why? Pump intake is clogged with metal shavings. Why? No filter on pump intake (as designed)

Root Cause


4. Root Cause Analysis Waterleaks on the left side tail light T/M leaving gaps in finish T/M not turning spatula into the seam T/M not instructed in proper angle of finish when trained No specification in STW for proper spatula angle when finishing

ROOT CAUSE

*Apply the “therefore” test to check thinking

Example through Step 4


14

4. Root Cause Analysis FMLA paperwork is not received from TMR by the payroll deadline Form doesn't pass review Form was submitted incorrectly Part "D" not complete T/M thought HR was to complete Instructions not clear in Part "D"

*Apply the “therefore” test to check thinking

Example through Step 4


Example Step 4 44

8 Steps

Proceedings

Step 1. Clarify the problem


(1) Clarify the “Ultimate Goal” of your responsibilities & work (2) Clarify the “Standard” of your work (3) Clarify the “Current Situation” of your work (4) Visualize the gap between the “Current Situation” and the “Standard” (1) Break down the problem


(2)Make Identify the prioritized problem (1) a commitment (3)Set Specify the point of occurrence by checking (2) measurable, concrete and challenging targets the process through GENCHI GENBUTSU

Step 4. Analyze the root cause (1) Examine the point of occurrence and think of possible causes without

(1)prejudice Develop as many potential countermeasures

Step 5. Develop countermeasures

(2) Gather through GENCHI GENBUTSU and keep asking “Why?” as facts possible (3) Specify the root cause (2) Select the highest value added countermeasures (3) Build consensus with others (4) Develop a clear and detailed action-plan

Step 5) Develop Countermeasures

45

15

Procedure for developing countermeasures Countermeasure Countermeasure Countermeasure

Root Cause

Countermeasure Countermeasure with the highest value-added Countermeasure Countermeasure Countermeasure

Step 5 - Develop Countermeasures 46

Select the highest value added Countermeasures Evaluate all potential Countermeasures Effectiveness

Truly eliminates the Root Cause Meets the Target

Cost/Manpower

The cost and time Number of people required to implement/to sustain

Risk

The risks when implementing Safety? Quality? Workability? Impact on other previous or following processes


Build consensus with others Present to management for approval to go forward— A-3 format is a standardized and efficient tool •Explain and discuss plans with all relevant parties • Set up a cross functional committee • Organize the meeting to present the analysis and countermeasure ideas/plans • Hold update meetings to share latest info/progress Note: thru Process step 5, planning phase is completed


16

Select the highest value-added Countermeasures Make an evaluation matrix: Countermeasure for assembling mismatched parts Risk Overall judgment

Workability

Problems to other processes

Safety problem

Quality problem

Technical difficulty

Expected effort

Options

Cost / Man-hour

Factors

Change parts color Change parts shape

X X X

X

X X

Good Acceptable

Change sequence of operation

NG Optimal

Confirm the facts by interviewing related people and departments

Step 5 -Develop Countermeasures 49

Develop a clear and detailed action-plan When creating the action-plan, be sure to clearly identify the four W’s of the countermeasures Who – What – Where – When? Clarify the roles and responsibilities of people and departments involved

Keep updates (point to be checked) through reporting, informing, and consulting

Clarify the schedule and order of actions to implement

(Example)Action Plan Action items Determine the best color for parts per model

Operator

A

July August September 1W 2W 3W 4W 1W 2W 3W 4W 1W 2W 3W Discuss color Discuss and decide in a team meeting

Request to prepare Prepare trial parts

Test by using trial parts

B

Confirm test results Report to managers


5. Develop Countermeasure R.C. No spec in standard work for spatula angle Cost

Safety

Add inspection process

∆

∆

O

∆

∆

Train T/M's in correct angle to hold spatula

Effort

∆

O

O

Effectiveness

O

Overall

O

Repair in CART

X

X

O

X

X

Temp Action Add inspection key points at quality gate and feeback to T/M's ‐ 7/28

Make a Plan

Example: Step 5 51

17

5. Countermeasure Options & Evaluation Options

Effectiveness

Budget

Speed

Quality

Overall Assessment

Post clearer instructions on T/M board

X

O

O

X

X

O

O

O

O

Update instructions on form Have TMR instruct T/M Update instructions on form along with TMR communications

O

O

Comments -Create awareness of enhancement -Help T/Ms who review board -Not helpful at home -Would document enhancement as new standard -Dependent on T/M reading it -Verbally communicate the enhancement -Cannot ensure that T/M will remember the instructions if not written down

O

O

-Would document enhancement as new Standard while confirming the instructions

Example: Step 5 52



Step 3. Set a target Step 4. Analyze the root cause


Proceedings (1) Clarify the “Ultimate Goal” of your responsibilities & work (2) Clarify the “Standard” of your work (3) Clarify the “Current Situation” of your work (4) Visualize the gap between the “Current Situation” and the “Standard” (1) Break down the problem (2) Identify the prioritized problem (3) Specify the point of occurrence by checking the process through GENCHI GENBUTSU (1) Make a commitment (2) Set measurable, concrete and challenging targets (1) Examine the point of occurrence and think of possible causes without prejudice (2) Gather facts through GENCHI GENBUTSU and keep asking “Why?” (3) Specify the root cause (1) Develop as many potential countermeasures as possible (2) Narrow down the countermeasures to the most practical and effective (3) Build consensus with others (4) Develop a clear and detailed action-plan

Step 6 - See Countermeasures Through 53

8 Steps Step 6. See countermeasures through

Proceedings (1) With all members united, implement countermeasures with speed and persistence (2) Share information with others by informing, reporting and consulting (3) Never give up, and proceed to the next step quickly

Step 6 - See Countermeasures Through 54

18

Implement Countermeasures with speed and persistence after consensus (Nemawashi) building

1) Concentrate efforts 2) Check progress regularly “On-the-floor” standup at the progress boards— relate to “jishuken” room

Step 6) See Countermeasures Through 55

6. See Countermeasure Through Countermeasure Plan - Train T/M's in correct spatula angle

What

Who

When

Status

Rewrite Standard Work

T/L

7/28

100%

Develop SWES with Key Points

T/L

7/29

100%

Train T/M's

T/L

7/30&31

100%

Check for 3 Shifts

T/L

8/3

100%

Remove Temp Action

T/L

7/30

100%

Additional tracking method -

100%Complete

25% Complete

75% Complete

50% Complete

Example: Step 6 56

6. Action Plan Item (What) (When)

Resp (Who)

Timing Feb W1

Draft form with clearer instructions

W2

W3

Mar W4

W1

W2

W3

W4

TH

Sample T/M response; revise as needed

TH

Consensus/Approval throughout HR

RK

Coordinate communication method with TMR and roll out

SE

Example: Step 6 57

19

Good Acceptable NG Optimal

Example through Steps 5 & 6 58



Step 3. Set a target Step 4. Analyze the root cause Step 5. Develop countermeasures


Step 7 - Evaluate Both Results and Processes 59

8 Steps Step 6. See Countermeasures Through

Step 7. Evaluate Both Results and Processes


(1) Evaluate the results and the processes, and share it with members involved (2) Evaluate from three key perspectives: Customer’s, 8 Step’s, and Your Own (3) Understand the reasons of success and failure


20

Evaluate results and process, and share it with stakeholders Evaluate the process for achieving the results Did we analyze the true root cause?

What was most effective?

Did we follow the Problem solving 8 steps completely?


Evaluate results and processes, and share it with stakeholders

Confirm positive and negative effects

Positive effects Repair hours

Achieved target Negative effects

Cost for machine modification


Develop a tracking chart or graph (make the standard/target easy to see • Where do we get the data? • What data is needed? • What is the required time period? • Who will collect and summarize data?

Step 7 Execution 63

21

7. Monitor Both Results and Processes Tail light Waterleak Tracking 7/28

8 defects

7/29

0 defects

7/30

0 defects

7/31

0 defects

8/1 8/2

0 defects 0 defects

8/3

0 defects

Tail Light Waterleaks

Remove Temp Action

10 8 6 4 2 0

# of defects 7/28

7/29 7/30 7/31 8/1 8/2 8/3 Date

Example: Step 7 64

7. Monitor Both Results and Processes Number of FMLA forms from TMR not meeting payroll deadline

250 200

193

150 100

100

98

W2

W3

50

20

19

W4

May W1

6

0

W2

W3

0 April W1

Example: Step 7 65




Step 4. Analyze the root cause



Step 8 - Standardize Successful Processes 66

22

8 Steps Step 6. See Countermeasures Through

Step 7. Evaluate Both Results and Processes

Step 8. Standardize Successful Processes


(1)Evaluate the results and the processes, and share it with members involved (2)Evaluate from three key perspectives: Customer’s, 8 Step’s, and Your Own (3)Understand the reasons of success and failure

(1) Set successful processes as new standard (2) Share the new standard (YOKOTEN) (3) Start the next round of KAIZEN


Procedure for Standardizing successful processes (1) Successful processes as new standard Overall Company Own work area

(2) Share the new standard (YOKOTEN)

Ideal Situation

KAIZEN Standardization

(3) Start the next round of KAIZEN

YOKOTEN

KAIZEN Standardization

YOKOTEN

KAIZEN

Success

Standardization

YOKOTEN

Implementation


Start the next round of KAIZEN Kaizen Standardize Solve one problem Repetition of problem solving process

KAIZEN KAIZEN KAIZEN


23

8. Standardize Successful Processes Yokoten: Contact other NAMC's to confirm no problem Follow-up: Have Pilot add special check for finish angle in Standardized work development

Example: Step 8 70

8.

Standardize Successful Performance

Document reason for adding additional instructions to form Standardize electronic form in database with revision date Yokoten: Share the new form with other NAMCs by June 30

Example: Step 8 71

5. Develop Countermeasure

1. Clarify the Problem Ultimate Goal:

No waterleaks in TMMK produced cars

R.C. No spec in standard work for spatula angle Effort

Zero audit defects from Sealer area

Ideal Situation (Standard): Current Situation:

7 waterleaks on 7/28

10

∆

Effectivenes s

Ove rall

O

∆

∆

O

O

O

O

X

X

O

X

X

Temp Action Add inspection key points at quality gate and feeback to T/M's ‐ 7/28

Gap = 7 Actual

∆

Safety

∆

Repair in CART

7

5

Cost

Train T/M's in correct angle to hold spatula

Add inspection process 15

Goal

2. Break Down the Problem

6. See Countermeasure Through 7 Water leaks

1 on Avalon

Countermeasure Plan - Train T/M's in correct spatula angle

6 on Camry

1 in Mohican

5 Tail light

1 side

Vehicle Type


What

Who

Rewrite Standard Work

T/L

Develop SWES with Key Points

When

Status

7/28

100%

T/L

7/29

100%

Train T/M's

T/L

7/30&31

100%

Check for 3 Shifts

T/L

8/3

100%

Remove Temp Action

T/L

7/30

100%

Process Prioritized Problem

C/M Complete

C/M Identified

C/M Tracking

C/M Implemented

Go and See Investigation for Point of Occurrence 1) Floor Brush--Finish lower seam on end panel 2) Engine Room Finish--Finsh the area just above and below the tail light Engine Room

Floor Brush

Trunk Brush

2nd Application

Finish Hood Corner

Finish Rear Hood

Finish Mirror Plate



7. Monitor Both Results and Processes Engine Room Finish

Tail light Waterleak Tracking


Point of Occurrence

3. Target Setting

7/28

8 defects

7/29

0 defects

7/30

0 defects

7/31

0 defects

8/1

0 defects

8/2

0 defects

8/3

0 defects

Tail Light Waterleaks

# of defects

1st Application

Remove Temp Action

10 8 6 4 2 0

7/28

7/29 7/30 7/31 8/1 8/2 8/3 Date

Target: Eliminate 5 tail light area water leaks on Camry by 7/29

8. Standardize Successful Processes

4. Root Cause Analysis

Yokoten: Contact other NAMC's to confirm no problem

Waterleaks on the left side tail light T/M leaving gaps in finish T/M not turning spatula into the seam

Follow-up: Have Pilot add special check for finish angle in Standardized work development

T/M not instructed in proper angle of finish when trained No specification in STW for proper spatula angle when finishing

ROOT CAUSE

Example: Steps 1-8 72

24

Example: Steps 1-8

73

Example: Steps 1-8 74

25

8 Step Problem Solving Method - University of Kentucky

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