Rational Number Word Problems

These lessons help Grade 7 students learn how to solve real-world and mathematical problems involving the four operations with rational numbers.

Common Core: 7.NS.3

Suggested Learning Targets

• I can solve mathematical and real-world problems involving four operations with rational numbers. (Tom had pieces of rope. Rope 1 was 5 ½ feet long. Rope 2 was 74 inches long. Rope 3 was 1 ½ yards long. What is the total length of rope?)

• I can justify the steps taken to solve multi-step mathematical and real-world problems involving rational numbers.

Solve real-world problems involving the four operations with rational numbers (7.NS.3)
In this lesson you will learn to use addition and subtraction to solve real-world problems involving decimals by analyzing the situation described in the problem.

Example 1: A recipe for trail mix calls for 3/4 cup dried fruits, 1/2 cup mixed nuts, and 1/3 cup granola. How many cups of trail mix does this recipe make?

Example 2: Anastasia was 19 1/4 inches at birth. At her 3 month checkup, she measures 23 1/2 inches. How much has she grown?

Example 3: The Darwin D. Martin house, built by Frank Lloyd Wright, has a rectangular stained glass window with a length of 41 1/2 feet and a width of 26 1/4 feet. What is the area of the window?

Example 4: You are an editor for your school yearbook. Each row of photos is 8 5/8 inches wide, including the margin. Each photo is 1 1/4 inches wide, the space between each photo is 1/8 inch, and each margin is 1/4 inch. How many photos can fit in one row?

Rational number word problem

Example:
Most liquids when cooled will simply shrink. Water on the other hand, actually expands when it is frozen. Its volume will increase by about 9 percent, Suppose you have one third of a gallon of water that gets frozen. What is the volume of the ice?

Rational number word problem

Example:
In the year 1944, computers weighed as much as 4,500 kilograms. A modern laptop weighs around 2.7 kilograms. What is the ratio of how much computers weighed in 1944 to how much a modern laptop weighs? (Express your answer as a ratio of two integers)

Rational number word problem

Example:
Shares of stock represents how much of a company or person owns. Puff incorporated is owned by Peter, Paul and Mary. Peter owns 4,050 shares, Paul owns 2,510 shares and Mary owns 5600 shares. Suppose the company made a profit this year of \$1,500,000. If each shareholder gets a proportion of the total profit that is equal to the proportion of the share they own. How much money does Mary receive? (Round to the nearest penny)

Rational Number Word Problems and PEMDAS

Examples:

1. The science teacher is filling her new fish aquarium. The aquarium holds 40 gallons. If she fills the aquarium 4/5 of the way full, how many gallons will she need?

2. A baker needs to make 8 batches of cookies for a party. If each batch requires 2 3/4 cups of flour, how many cups will he need?

3. Mike is putting up a fence in the back yard. The fence comes in sections that are 4 2/3 feet long. If the yard is 34 feet long, how many sections will he need to buy?

4. Bella volunteers to make cookies for her math class. Each batch of cookies requires 1 2/3 cups of flour. If she has 12 cups of flour, how many batches of cookies can she make?

5. Trey is buying a computer on sale. The original price was \$1,200. If the sale price is 5/6 of the original price, how much did Trey pay for the computer?

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.