Problem Solving Strategies: Understanding, and using the Guess and Check method.

Once upon a time when I was in grade school, the guess and check method could keep me up all night trying to “guess” the correct answer, and “checking” my guess to see if it fits. In today’s math classes, teachers are teaching students a much more quicker and efficient way to guess and check. Below I will demonstrate the process.

Example Problem: Mr. Young has 32 18-cent stamps and 27-cent stamps all told. The stamps are worth $7.65. How many of each kind of stamp does he have?

Now instead of blindly guessing numbers, teachers are teaching students to start guesses with multiples of ten. Watch below:

*Note: if you guess 20 stamps you have to do 12 for the 27-cent (32-20=12)

Guess #1) 18 X 20 + 27 X 12=$6.84

This first guess is too low for our $7.65 total, so now let’s take and use 10:

Guess #2) 18 X 10 + 27 X 22 =$7.74

Now this is an extremely close guess. For you next guess, you’re going to want to increase by just one:

*Note: because you are guessing 11 don’t forget to minus 11 from 32 to get 21 for the 27-cent to be multiplied by.

Guess #3) 18 X 11 + 27 X 21 =$7.65

Tadah, we just learned how to do a guess and check problem in less than a minute!

I really wish I could have learned this technique back in my day. Children these days are so much more fortunate in the methods they learn for solving math problems.