# McGraw Hill Math Grade 4 Chapter 5 Lesson 5 Answer Key Using Mental Math to Multiply

Practice the questions of McGraw Hill Math Grade 4 Answer Key PDF Chapter 5 Lesson 5 Using Mental Math to Multiply to secure good marks & knowledge in the exams.

## McGraw-Hill Math Grade 4 Answer Key Chapter 5 Lesson 5 Using Mental Math to Multiply

Multiply

Find each product using mental math.

Question 1.
10 × 300 = 300
Explanation:
1 x 3 = 3
The number of zeros in the product is same as the number of zeros in the factors
If the product ends with zero then add the zeros to the result

Question 2.
40 × 90 = ____
4 x 9 = 36
so, 3600
40 x 90 = 3600
Explanation:
The number of zeros in the product is same as the number of zeros in the factors
If the product ends with zero then add the zeros to the result

Question 3.
400 × 30 = ___
4 x 3 = 12
so, 400 x 30 = 12000
Explanation:
The number of zeros in the product is same as the number of zeros in the factors
If the product ends with zero then add the zeros to the result

Question 4.
800 × 70 = ___
8 x 7 = 56
so, 800 x 70 = 56000
Explanation:
The number of zeros in the product is same as the number of zeros in the factors
If the product ends with zero then add the zeros to the result

Question 5.
500 × 40 = ___
5 x 4 = 20
so, 500 x 20 = 20000
Explanation:
The number of zeros in the product is same as the number of zeros in the factors
If the product ends with zero then add the zeros to the result

Question 6.
25 × 600 = ___
25 x 6 = 150
so, 25 x 600 = 15000
Explanation:
The number of zeros in the product is same as the number of zeros in the factors
If the product ends with zero then add the zeros to the result

Question 7.
40 has one zero. 500 has two zeros. Why does the product of 40 and 500 have four zeros? Explain.