Go through the Math in Focus Grade 3 Workbook Answer Key Chapter 7 Practice 1 Mental Multiplication to finish your assignments.

## Math in Focus Grade 3 Chapter 7 Practice 1 Answer Key Mental Multiplication

**Multiply mentally. Fill in the missing numbers.**

Example

Find 4 × 7

4 × 7 is the same as 7 × 4.

So, 4 × 7 = __28__

Question 1.

Find 3 × 9

3 × 9 is the same as 9 × 3.

So, 3 × 9 = ____

Answer:

3 × 9 = 9 × 3 =27.

Explanation:

Given that 3 × 9 is the same as 9 × 3,

So, 3 × 9 which is 27, and 9 × 3 is also 27.

Question 2.

Find 5 × 7

5 × 7 is the same as 7 × 5.

So, 5 × 7 = ____

Answer:

5 × 7 = 7 × 5 = 35.

Explanation:

Given that 5 × 7 is the same as 7 × 5,

So, 5 × 7 which is 27, and 7 × 5 is also 35.

Question 3.

Find 9 × 8

9 × 8 is the same as 8 × 9.

So, 9 × 8 = ____

Answer:

9 × 8 = 8 × 9 = 72.

Explanation:

Given that 9 × 8 is the same as 8 × 9,

So, 9 × 8 which is 72, and 8 × 9 is also 72.

**Multiply mentally. Fill in the missing numbers.**

Example

3 × 50 = 3 × 5 tens

= __15__ tens

= __150__

Question 4.

3 × 500 = 3 × 5 hundreds

= ___ hundreds

= _____

Answer:

3 × 500 = 1500.

Explanation:

Given that

3 × 500 = 3 × 5 hundreds

= 15 hundreds

= 1500.

Question 5.

7 × 40 = 7 × 4 tens

= ___ tens

= _____

Answer:

7 × 40 = 280.

Explanation:

Given that

7 × 40 = 7 × 4 tens

= 28 tens

= 280.

Question 6.

7 × 400 = 7 × 4 hundreds

= ___ hundreds

= _____

Answer:

7 × 400 = 2800.

Explanation:

Given that

7 × 400 = 7 × 4 hundreds

= 28 hundreds

= 2800.

Question 7.

8 × 60 = 8 × 6 tens

= ___ tens

= _____

Answer:

8 × 60 = 480.

Explanation:

Given that

8 × 60 = 8 × 6 tens

= 48 tens

= 480.

Question 8.

8 × 600 = 8 × 6 hundreds

= ___ hundreds

= _____

Answer:

Explanation:

Given that

8 × 600 = 8 × 6 hundreds

= 48 hundreds

= 4800.

**Multiply mentally.**

Question 9.

9 × 20 = ___

Answer:

9 × 20 = 180.

Explanation:

The mental multiply of 9 × 20 is, as 9 × 2 is 18.

So 9 × 20 = 180.

Question 10.

9 × 200 = ___

Answer:

9 × 200 = 1800.

Explanation:

The mental multiply of 9 × 200 is, as 9 × 2 is 18.

So 9 × 200 = 1800.

Question 11.

2 × 70 = ___

Answer:

2 × 70 = 140.

Explanation:

The mental multiply of 2 × 70 is, as 2 × 7 is 14.

So 2 × 70 = 140.

Question 12.

2 × 700 = ___

Answer:

2 × 700 = 1400.

Explanation:

The mental multiply of 2 × 700 is, as 2 × 7 is 14.

So 2 × 700 = 1400.

Question 13.

8 × 30 = ___

Answer:

8 × 30 = 240.

Explanation:

The mental multiply of 8 × 30 is, as 8 × 3 is 24.

So 8 × 30 = 240.

Question 14.

8 × 300 = ____

Answer:

8 × 300 = 2400.

Explanation:

The mental multiply of 8 × 300 is, as 8 × 3 is 24.

So 8 × 300 = 2400.