Problem Solving Strategies Guess And Check

Process Problem 1
Marty did 2 of these activities. He paid for them with a $10.00 bill. His change was $3.75. What 2 activities did Marty do? (Hint: Make a guess. Then analysis your guess.)
Activity Cost
Movies $3.50
Putt-Putt Golf $3.00
Skating $2.00
Go-Kart Rides $2.75
Understanding the Problem
· How abounding activities did he do? (2)
· How abundant money did he have? ($10.00)
· What was his change? ($3.75)
Planning a Solution
· How abundant money did he have? ($10.00) What was the change? ($3.75)
· How abundant did he spend? ($6.25)
· If he saw the movies and golfed, how abundant money would he accept spent? ($6.50) Did he do these 2 activities? (No, they amount too much.)
Finding the Answer
Guess and Check
· Try movies and skating—$3.50 + $2.00 = $5.50. (too little)
· Try movies and go-karts—$3.50 + $2.75 -- $6.25. (correct)
The activities that Marty did are the movies and the go-kart rides.
Problem Extension
Marty's acquaintance Joe went also, but he was not bound to 2 activities. He took $10.00 and brought back$2.25. What activities did he do? (golf, skating, go-kart rides)


Process Problem 2
I wrote 5 altered numbers on 5 cards. The sum of the numbers is 15. What numbers did I put on the cards? (Hint: Make a guess. Then analysis your guess.)
Understanding the Problem
· How abounding numbers did I write? (5)
· What is the sum of the numbers? (15)
· How abounding numbers on anniversary card? (1)
· Are any 2 numbers the same? (No, they are all different.)
Planning a Solution
· Could 1 of the numbers be 15? (No, because the blow would be 0 and we said that all the numbers were different.)
· Select 5 numbers and analysis to see if their sum is 15.
Finding the Answer
Guess and Check
· Try 0,1,2,3,4—0 + 1 + 2 + 3 + 4 = 10 (too little)
· Try 1,2,3,4,5—1 + 2 + 3 + 4 + 5 - 15 (correct)
The numbers are 1, 2, 3, 4, and 5.
Problem Extension
If the numbers are even and altered and their sum is 30, what are the numbers? (2,4,6,8,10)

Process Problem 3
David's age this year is a assorted of 5. Next year, David's age will be a assorted of 7. How old is David now?
Understanding the Problem
· What do we apperceive about David's age this year? (multiple of 5)
· What do we apperceive about David's age next year? (multiple of 7)
Planning a Solution
· List some multiples of 5. (5, 10, 15, . . .) Multiples of 7. (7, 14, 21, . . .)
· Assumption what David's age ability be this year and add 1 to it to see if that amount is a assorted of 7. (See solution.)
Finding the Answer
Guess and Check
· Try 10 and 11. (No, 11 is not a assorted of 7.)and so on
Make an Organized List
Multiples of 5 5 10 15 20
Multiples of 7 7 14 21 28
David is 20 years old now.
Problem Extension
In how abounding added years will David's age be a assorted of both 5 and 7? (In 15 years, if he is 35)