Section B Section B Checkpoint

Problem 1

Find the value of $18 \times 7$ . Explain or show your reasoning.

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Solution

$18 \times 7 = 126$ . Sample response:

$70 + 56 = 126$

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Sample Response

$18 \times 7 = 126$ . Sample response:

$70 + 56 = 126$

Problem 2

Find the value of $27 \times 36$ . Explain or show your reasoning.

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Solution

972. Sample response:

$600 + 120 + 210 + 42 = 972$

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Sample Response

972. Sample response:

$600 + 120 + 210 + 42 = 972$

Problem 3

Here is Noah’s work finding the value of $92 \times 78$ .

Do you agree with Noah’s work? Explain or show your reasoning.

multiply. ninety 2 times seventy 8. 7 rows.

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Solution

I disagree with Noah. Sample response: He multiplied 2 and 90 by 7 instead of by 70. Those partial products should be 10 times as much, 140 and 6,300 instead of 14 and 630.

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Sample Response

I disagree with Noah. Sample response: He multiplied 2 and 90 by 7 instead of by 70. Those partial products should be 10 times as much, 140 and 6,300 instead of 14 and 630.