Using Multiplication & Division to Solve

Problems Involving Rates

TEKS 6.2C

Lesson 7 (2nd 6 Weeks)

Ratios• A ratio is a comparison of two

quantities.

• When a ratio is written as a fraction, the first number is the numerator of the fraction and the second number is the denominator. EX: the ratio 1:5 = 1

5

• When a ratio is written with the two numbers separated by a colon, the colon is read as the word to and the ratio 1:5 is read one to five.

Rate• A rate is also a ratio.

EX: If you walk 7 miles in 2 hours, the ratio 7:2 refers to the rate at which you walk.

Use Multiplication & Division to Solve Problems Involving Ratios and Rates

• Use multiplication when you want to combine groups of equal size.

• Division is the opposite of multiplication. Use division when you want to separate a whole into groups of equal size.

EX: Using Multiplication

Tommy decided that he wanted to buy a new TV set at Wal-mart. He will make payments of $96 a month for a year. How much will Tommy pay for the TV at the end of the year?

Tommy decided that he wanted to buy a new TV set at Wal-mart. He will make payments of $96 a month for a year. How much will Tommy pay for the TV at the end of the year?

• We know that there is 12 months in a year. Since Tommy will be paying $96 a month. We need to multiply $96 by 12 to figure out the total amount of the TV.

Tommy decided that he wanted to buy a new TV set at Wal-mart. He will make payments of $96 a month for a year. How much will Tommy pay for the TV at the end of the year?

9612x2

1

1 90692511

1

+

Tommy will pay $1152 for the TV

in a year.

EX: Using Division

• A short order cook makes omelets at a breakfast diner. Each omelet takes 3 eggs. The cook has 36 eggs. How many omelets can he make?

363-3

1

06

2

- 60

The cook can make 12 omelets.