Name______

Beginning to Think about Children’s Strategies

The following examples illustrate strategies observed from actual children solving addition and subtraction word problems.

Consider the following word problem:

Six frogs were sitting on lily pads. 8 more frogs joined them. How many frogs were there then?

A group of second graders all answer “14” almost immediately.

Teacher: How do you know there were 14?

Rudy: Because 6 and 6 is 12, and 2 more is 14.

Denise: 8 and 8 is 16. But this is 8 and 6. That is 2 less, so it’s 14.

Theo: Well, I took one from the 8 and gave it to the 6. That made 7 and 7, and that’s 14.

Vanessa: 8 and 2 more is 10. You need 4 more to make the 6, together that makes 14.

Describe how the four children’s strategies are similar to each other.

Apply a strategy similar to each of the children’s for the problem:

Robin had 9 toy cars. How many toy cars will she have if she gets 5 more toy cars for her birthday?

Rudy:

Denise:

Theo:

Sandra:

Are there other ways that you can think of for solving this problem?

With the children’s strategies described on the previous page in mind, now try to solve problems that involve larger numbers. Can you predict how a child might solve these problems using methods that are in some way similar to the methods the four children used? Try to think of as many different strategies as you can and imagine that these children have not been taught the traditional methods (lining up the numbers with “carrying” or “borrowing”). Be prepared to share your thoughts in class.

  1. Kate had 29 dollars. For her birthday she got 62 dollars. How much money does Kate have now?
  1. Max had 44 comic books. For his birthday his dad gave him 19 more comic books. How many comic books does Max have all together?
  1. Lucy had 38 dollars. One weekend she earned 25 dollars raking leaves for her neighbors. How much money did Lucy have then?
  1. Kevin had 84 gumdrops. During a week he ate 29 gumdrops. How many gumdrops does he have left?
  1. James had 61 stickers. He gave 43 stickers to his friend. How many stickers did he have left?