Module 2 Lesson 18

Use basic facts to estimate quotients with two-digit divisors.

• 5.NBT.1 Recognize that in a multi-digit number, a digit in one place represents 10 times as much as it represents in the place to its right and 1/10 of what it represents in the place to its left.5.NBT.6 Find whole-number quotients of whole numbers with up to four-digit dividends and two- digit divisors, using strategies based on place value, the properties of operations, and/or the relationship between multiplication and division. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.

Common CoreStandards

Learning Targets

•I can use basic facts to estimate quotients with two-digit divisors.

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Count by six.

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Count by six tens.

When I raise my hand stop counting.

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Count by eights.

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Count by eight tens.

When I raise my hand stop counting.

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Count by nines.

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Count by nine tens.

When I raise my hand stop counting.

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12,000 ÷ 40

Write the division sentence

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12,000 ÷ 40

Write as a 2 step division sentencetaking out the ten

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12,000 ÷ 40

Rewrite after solving the first part of the division problem

12,000 ÷ 10 ÷ 4

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12,000 ÷ 40

Write the answer

12,000 ÷ 10 ÷ 4

1200 ÷ 4

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12,000 ÷ 400

Write the division sentence

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12,000 ÷ 400

Write as a 2 step division sentencetaking out the ten

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12,000 ÷ 400

Rewrite after solving the first part of the division problem

12,000 ÷ 100 ÷ 4

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12,000 ÷ 4000

Write the answer

12,000 ÷ 100 ÷ 4

120 ÷ 4

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12,000 ÷ 4000

Write the division sentence

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12,000 ÷ 4000

Write as a 2 step division sentencetaking out the ten

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12,000 ÷ 4000

Rewrite after solving the first part of the division problem

12,000 ÷ 1000 ÷ 4

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12,000 ÷ 4000

Write the answer

12,000 ÷ 1000 ÷ 4

12 ÷ 4

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360,000 ÷ 6,000

Write the division sentence

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360,000 ÷ 6,000

Write as a 2 step division sentencetaking out the ten

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360,000 ÷ 6,000

Rewrite after solving the first part of the division problem

360,000 ÷ 1000 ÷ 6

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360,000 ÷ 6,000

Write the answer

360,000 ÷ 1000 ÷ 6

360 ÷ 6

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490,000 ÷ 700

Write the division sentence

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490,000 ÷ 700

Write as a 2 step division sentencetaking out the ten

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490,000 ÷ 700

Rewrite after solving the first part of the division problem

490,000 ÷ 100 ÷ 7

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490,000 ÷ 700

Write the answer

490,000 ÷ 100 ÷ 7

4900 ÷ 7

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640,000 ÷ 80

Write the division sentence

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640,000 ÷ 80

Write as a 2 step division sentencetaking out the ten

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640,000 ÷ 80

Rewrite after solving the first part of the division problem

640,000 ÷ 10 ÷ 8

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640,000 ÷ 80

Write the answer

640,000 ÷ 10 ÷ 8

64,000 ÷ 8

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812 ÷ 39

Round the divisor to the nearest 10

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812 ÷ 39

Name the multiple of 40 that’s closest to 812

812 ÷ 40

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812 ÷ 39

Below 800 ÷ 40, write the answer

812 ÷ 40

812 ÷ 39 ≈ 800 ÷ 40

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183 ÷ 31

Round the divisor to the nearest 10

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183 ÷ 31

Name the multiple of 30 that’s closest to 183

183 ÷ 30

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183 ÷ 31

Below 180 ÷ 30, write the answer

183 ÷ 30

183 ÷ 31 ≈ 180 ÷ 30

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437 ÷ 72

Round the divisor to the nearest 10

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437 ÷ 72

Name the multiple of 70 that’s closest to 437

437 ÷ 70

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437 ÷ 72

Below 420 ÷ 70, write the answer

437 ÷ 70

437 ÷ 72 ≈ 420 ÷ 70

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823 ÷ 97

Round the divisor to the nearest 10

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823 ÷ 97

Name the multiple of 100 that’s closest to 823

823 ÷ 100

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823 ÷ 97

Below 800 ÷ 100, write the answer

823 ÷ 100

823 ÷ 97 ≈ 800 ÷ 100

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8,191 ÷ 92

Round the divisor to the nearest 10

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8,191 ÷ 92

Name the multiple of 90 that’s closest to 8,191

8,191 ÷ 90

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8,191 ÷ 92

Below 8100 ÷ 90, write the answer

8,191 ÷ 90

8,191 ÷ 92 ≈ 8100 ÷ 90

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Sandra bought 38 DVD movies for $874. Give an estimate of the cost

of each DVD movie.

Learn

Problem 1

8,095 ÷ 23

Which should round first,the whole or divisor?

Learn

Problem 1

8,095 ÷ 23

What’s 23 rounded to the nearest ten?

Learn

Problem 1

8,095 ÷ 23

Round 8,095 so it is easy to divide by 20

8,095 ÷ 20

Learn

Problem 1

8,095 ÷ 23

Round 8,095 so it is easy to divide by 20

8,095 ÷ 20

8,000 ÷ 20

Learn

Problem 1

8,095 ÷ 23

Round 8,095 so it is easy to divide by 20

8,095 ÷ 20

8,000 ÷ 20

8,000 ÷ 10 ÷ 2

800 ÷ 2

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Problem 2

2,691 ÷ 48

Which should round first,the whole or divisor?

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Problem 2

2,691 ÷ 48

What’s 48 rounded to the nearest ten?

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Problem 2

2,691 ÷ 48

Round 2,691 so it is easy to divide by 50

2,691 ÷ 50

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Problem 2

Round 2,691 so it is easy to divide by 50

2,500 ÷ 50

2,691 ÷ 48

2,691 ÷ 50

3,000 ÷ 50

Learn

Problem 2

Round 8,095 so it is easy to divide by 20

2,500 ÷ 10 ÷ 5

250 ÷ 5

2,691 ÷ 48

2,691 ÷ 50

2,500 ÷ 503,000 ÷ 50

3,000 ÷ 10 ÷ 5

300 ÷ 5

Learn

Problem 2

5,484 ÷ 71

Work independently to estimate

Learn

Problem 2

9,215 ÷ 95

Should we round the divisorup or down?

Practice

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