Word Problems with Weight

Lesson Plan - Get It!

Audio:

Word problems with weight are just like any other type of word or story problem.

We still have information that we know and a question that we need to answer. The only difference is that our answer will be in ounces, pounds, or tons!

Look at an example:

The grocer bags 5 pounds of groceries in each shopping bag. How many pounds of groceries are in 23 bags?

We can solve this problem like any other word problem:

• What do we know? We know that we have 5 pounds of groceries:
  • 5 pounds = 1 bag
• What do we need to find out? We need to find out how many pounds of groceries are in 23 bags:
  • x pounds = 23 bags
• We can multiply to find the answer:
  • 23 x 5 = 115
• There are 115 pounds in 23 bags of groceries.

In some word problems, we need to convert or change one unit of measurement to another. To convert units, we must know how the units are related. Read the conversion chart below to review the conversions between ounces, pounds, and tons:

When we need to convert between units, we can follow these four steps to solve the word problem:

1. Look at the Customary Units of Weight chart. What units will we need to convert to solve the problem?
2. How will we convert the units?

• To convert a larger unit to a smaller unit, we multiply.
• To convert a smaller unit to a larger unit we divide.

3. Convert the units.
4. Solve the problem.

Look at an example:

A bag of apples weighs 3 pounds. If Carmen takes a 4-ounce apple from the bag, how many ounces are left?

1. Convert from pounds to ounces. One pound equals 16 ounces.
2. Since a pound is a larger unit than an ounce, it will be necessary to multiply.
3. Convert the number of pounds in the bag by multiplying by 16 ounces:
   • 3 pounds x 16 ounces = 48 ounces
4. There are 48 ounces in the 3 pound bag of apples. Carmen removed a 4-ounce apple, so subtract 4 ounces from the 48 ounces in the bag:
   • 48 ounces – 4 ounces = 44 ounces

Solution: There are 44 ounces left in the bag.

In this section, you learned how to solve word problems using pounds, ounces, and tons. You also learned how to convert between measurement units before you solve a problem. Now you can solve problems when you go to the grocery store or supermarket!

It is time to practice these concepts.

In the Got It? section, you will use your new strategies to complete a step-by-step practice problem.