Whole Numbers and Multiplication Concepts

The video tutorial teaches how to estimate multiplication problems by rounding numbers to the nearest whole number. It demonstrates this technique with two examples: estimating 2.7 times 4 by rounding 2.7 to 3, and estimating 78 times 19.88 by rounding 78 to 80 and 19.88 to 20. The video emphasizes the importance of checking the reasonableness of the estimated results.

What is the nearest whole number to 2.7?

• 5

• 2

• 3

• 4

Tags

CCSS.5.NBT.B.7

Why is 1.2 an unreasonable estimate for 2.7 times 4?

• It is exactly the original number.

• It is less than the original number.

• It is greater than the original number.

• It is a negative number.

Tags

CCSS.3.OA.C.7

What is the product of 3 times 4?

• 12

• 13

• 11

• 10

Tags

CCSS.3.NBT.A.1

CCSS.4.NBT.A.3

What whole number is 78 closest to?

• 85

• 80

• 75

• 70

Tags

CCSS.5.NBT.A.4

What whole number is 19.88 closest to?

• 21

• 18

• 19

• 20

Tags

CCSS.4.NBT.B.5

What is the product of 80 times 20?

• 2000

• 2400

• 1600

• 1200

Tags

CCSS.4.NBT.B.6

How can 80 be expressed in terms of multiplication?

• 8 times 8

• 10 times 10

• 8 times 10

• 8 times 5

Tags

CCSS.3.OA.C.7

What is the result of multiplying 8 by 2?

• 15

• 14

• 16

• 17

Why is it unreasonable to get a smaller number than 80 when multiplying by a number close to 20?

• Because 80 is already a large number.

• Because multiplying by 20 should increase the number significantly.

• Because multiplication always increases the number.

• Because 20 is a small number.

What would you need to multiply 80 by to get 16,000?

• 200,000

• 20

• 200

• 2,000