Unit 5 Lesson 11 Using Long Division to Calculate Quotients

Problem 1

Use long division to show that the fraction and decimal in each pair are equal.

a. (3/4) and 0.75

Answer explanation

3 divided by 4

place the 3 inside the division box (dividend)

place the 4 outside of the division box (divisor)

you will need to add a decimal point at the end of the 3 and then add 2 more zeros to work out the problem.

Divide: 4 goes into 30 tenths 7 times

Multiply: 28

Subtract: 2

Bring Down the 0: 20

Divide: 4 goes into 20 hundredths 5 times

Multiply: 20

Subtract: 0

0.75

Problem 1

Use long division to show that the fraction and decimal in each pair are equal.

b. (3/50) and 0.06

Answer explanation

3 divided by 50

place the 3 inside the division box (dividend)

place the 50 outside of the division box (divisor)

you will need to add a decimal point at the end of the 3 and then add 2 more zeros to work out the problem.

Divide: 50 goes into 300 hundredths 6 times

Multiply: 300

Subtract: 0

0.06

Problem 1

Use long division to show that the fraction and decimal in each pair are equal.

c. (7/25) and 0.28

Answer explanation

7 divided by 25

place the 7 inside the division box (dividend)

place the 25 outside of the division box (divisor)

you will need to add a decimal point at the end of the 7 and then add 2 more zeros to work out the problem.

Divide: 25 goes into 70 tenths 2 times

Multiply: 50

Subtract: 20

Bring Down the 0: 200

Divide: 25 goes into 200 hundredths 8 times

Multiply: 200

Subtract: 0

0.28

Problem 2

Mai walked (1/8) of a 30-mile walking trail. How many miles did Mai walk? Explain or show your reasoning.

Answer explanation

Find 1/8 of 30

30 / 8

30 divided by 8

place the 30 inside the division box (dividend)

place the 8 outside of the division box (divisor)

you will need to add a decimal point at the end of the 30 and then add 2 more zeros to work out the problem.

Divide: 8 goes into 30 ones 3 times

Multiply: 24

Subtract: 6

Bring Down the 0: 60

Divide: 8 goes into 60 tenths 7 times

Multiply: 56

Subtract: 4

Bring Down the 0: 40

Divide: 8 goes into 40 hundredths 5 times

Multiply: 40

Subtract: 0

3.75

Problem 3

Use long division to find each quotient. Write your answer as a decimal.

a. 99 ÷ 12

Answer explanation

99 divided by 12

place the 99 inside the division box (dividend)

place the 12 outside of the division box (divisor)

you will need to add a decimal point at the end of the 99 and then add 2 more zeros to work out the problem.

Divide: 12 goes into 99 ones 8 times

Multiply: 96

Subtract: 3

Bring Down the 0: 30

Divide: 12 goes into 30 tenths 2 times

Multiply: 24

Subtract: 6

Bring Down the 0: 60

Divide: 12 goes into 60 hundredths 5 times

Multiply: 60

Subtract: 0

8.25

Problem 3

Use long division to find each quotient. Write your answer as a decimal.

b. 216 ÷ 5

Answer explanation

216 divided by 5

place the 216 inside the division box (dividend)

place the 5 outside of the division box (divisor)

you will need to add a decimal point at the end of the 216 and then add 1 more zero to work out the problem.

Divide: 5 goes into 21 tens 4 times

Multiply: 20

Subtract: 1

Bring Down the 6: 16

Divide: 5 goes into 16 ones 3 times

Multiply: 15

Subtract: 1

Bring Down the 0: 10

Divide: 5 goes into 10 tenths 2 times

Multiply: 10

Subtract: 0

43.2

Problem 3

Use long division to find each quotient. Write your answer as a decimal.

c. 1,988 ÷ 8

Answer explanation

1988 divided by 8

place the 1988 inside the division box (dividend)

place the 8 outside of the division box (divisor)

you will need to add a decimal point at the end of the 1988 and then add 1 more zero to work out the problem.

Divide: 8 goes into 19 hundreds 2 times

Multiply: 16

Subtract: 3

Bring Down the 8: 38

Divide: 8 goes into 38 tens 4 times

Multiply: 32

Subtract: 6

Bring Down the 8: 68

Divide: 8 goes into 68 ones 8 times

Multiply: 64

Subtract: 4

Bring Down the 0: 40

Divide: 8 goes into 40 tenths 5 times

Multiply: 40

Subtract: 0

248.5

Problem 4

To find the decimal of (9/25), Tyler reasoned:

(9/25) is equivalent to (18/50) and (36/100) so the decimal of (9/25) is 0.36.

a. Use long division to show that Tyler is correct.

Problem 4

To find the decimal of (9/25), Tyler reasoned:

(9/25) is equivalent to (18/50) and (36/100) so the decimal of (9/25) is 0.36.

b. Is the decimal of (18/50) also 0.36? Use long division to support your answer.

Problem 5

Complete the calculations so that each shows the correct difference.

a. 5 - ________ = 4.329

Answer explanation

You can take the answer (difference) and subtract it from the top number (minuend) of the math problem to find the bottom number (subtrahend).

5.000 - 4.329 = 0.671