Grades 3-5 Math Problem Solving in Action_ Getting Students to Love Word Problems

102 ◆ Reasoning About Problems

Thinking About Others Thinking

There is a specific genre of word problem types that ask students to think
about the thinking of others and then respond (see Figure 6.23). Here are
a few of the problems in this genre:

• Can you use Mike’s strategy?


• Can you convince me?


• Can you find and fix the error?


• Two-argument problems

Can You Think Like Mike?

Baseball cards were on sale at the toy store. They cost $1.50 each.

Nathan had $33. How many can he buy? If his mom will give him

enough to buy one more, how much will he need from her?

Students should have many opportunities to work with decimal problems.

My dad has 24 feet of wood. He is going to make 5 bookshelves. How

much wood would he use for each shelf if they are going to be the

same size?

Students should know that in this type of measurement problem, we can keep

the fraction remainder as part of the answer.

Figure 6.23 Unpacking Strategies

Mike said that when he saw 125 ÷ 25, he instantly thought, “What

times 25 equals 125?” Can you use his strategy to think about 400 ÷^ 8?

A.^ Solve using Mike’s method.

Step 1:^ 8 ×?^ =^400

Step 2:^ We know that 8 × 5^ =^40

Step 3:^ So 8 × 50^ =^400

B.^ Explain what you^ did.

I know that 8 × 5 = 40; therefore, 40 ÷ 8 = 5 so we now under-

stand that 40 0 ÷ 8 = 50