Multiplying Numbers Close to 100

The video tutorial introduces a math trick for multiplying two-digit numbers close to 100. It explains the method through several examples, demonstrating how to quickly calculate products by identifying how much each number is less than 100, subtracting, and then multiplying the differences. The tutorial also covers exceptions and provides tips for handling larger differences. The trick is shown to be effective for numbers close to 100, but less so for numbers below 80.

What is the first step in the trick for multiplying numbers close to 100?

• Add the numbers together

• Subtract the numbers from 100

• Find how much each number is less than 100

• Multiply the numbers directly

Tags

CCSS.5.NBT.B.5

In the example 97 times 96, what is the result of subtracting the smaller difference from the larger number?

• 95

• 94

• 92

• 93

Tags

CCSS.4.NBT.B.5

For the example 93 times 91, what is the product of the differences from 100?

• 56

• 63

• 81

• 72

Tags

CCSS.5.NBT.A.2

In the example 89 times 96, what is the result of subtracting the smaller difference from the larger number?

• 85

• 86

• 88

• 87

Tags

CCSS.4.NBT.B.5

What is the product of the differences in the example 89 times 96?

• 44

• 48

• 52

• 56

Tags

CCSS.4.NBT.B.5

In the example 82 times 90, what do you do with the product of the differences if it exceeds two digits?

• Multiply it by 10

• Subtract it from the left part of the result

• Add it to the left part of the result

• Ignore the extra digit

Tags

CCSS.4.NBT.B.5

What is the final result of 82 times 90 using the trick?

• 7,662

• 7,562

• 7,462

• 7,762

Tags

CCSS.5.NBT.B.5

In the example 98 times 90, what is the result of subtracting the smaller difference from the larger number?

• 87

• 89

• 88

• 86

Tags

CCSS.4.NBT.B.5

What is the product of the differences in the example 98 times 90?

• 21

• 20

• 19

• 18

Tags

CCSS.5.NBT.B.5

What is the final result of 98 times 90 using the trick?

• 8,840

• 8,850

• 8,830

• 8,820

Tags

CCSS.5.NBT.B.5