Mathematics, Problem Solving

Grade 3- 5

Objective

Students will learn how to recognize extra information in word problems.

Directions

Facts to Know
Sometimes a problem has extra information that students do not need to solve the problem. Before students start these problems, ask them these four important questions:

1. What does the problem ask you to find?
2. What information is needed to solve the problem?
3. How can you show the problem with numbers?
4. What is your answer?

Sample A
At the art fair, Libby bought a mug of root beer for $1, a veggie burger for $2, a hot fudge sundae for $2, and a piece of pottery for $5. How much did Libby spend on food?
First, have students focus on the information they need to answer the question being asked. Then they can identify the extra information that is not necessary for answering the question because it has no effect on the answer.
In the problem above, the question is about money spent on food. So the extra information is that Libby bought a piece of pottery for $5. Now, they can solve the problem using only the information that's necessary. $1 + $2 + $2 = $5-Libby spent $5 on food.
Sample B
Erica and her friends had a pizza party. They ordered 8 pizzas. 1/2 of the pizzas were large combo pizzas, 1/4 of the pizzas were medium specialty pizzas, and 1/4 were medium pepperoni pizzas. They also ordered five 2-liter sodas for $1.50 each. How many medium pepperoni pizzas did Erica and her friends order?
First, have students focus on the information they need to answer the question being asked. Then they can identify the extra information that is not necessary for answering the question because it has no effect on the answer.
In the problem above, the question is about how many medium pepperoni pizzas were ordered. So the extra information is how many sodas and large combo pizzas were ordered by Erica and her friends. Now you can solve the problem using only the information that's necessary. Erica and her friends ordered 2 medium pepperoni pizzas. 1/2 of 8 pizzas is 4 pizzas; 1/4 of 8 pizzas is 2 pizzas

Resources

• copies of the activity sheets (see the link below)