Practice the questions of **McGraw Hill Math Grade 4 Answer Key** **PDF Chapter 4 Lesson 1 Prime and Composite Numbers** to secure good marks & knowledge in the exams.

## McGraw-Hill Math Grade 4 Answer Key Chapter 4 Lesson 1 Prime and Composite Numbers

**Identify
**

**Identify each number as prime or composite.**

Question 1.

4

__composite__

Answer:

4 = composite number.

Explanation:

Factors of 4:

1 × 4 = 4.

2 × 2 = 4.

Question 2.

7 _____

Answer:

7 = Prime number.

Explanation:

Factors of 7:

1 × 7 = 7.

Question 3.

12 _____

Answer:

12 = Composite number.

Explanation:

Factors of 12:

1 × 12 = 12.

2 × 6 = 12.

3 × 4 = 12.

Question 4.

29 _____

Answer:

29 = Prime number.

Explanation:

Factors of 29:

1 × 29 = 29.

Question 5.

58 _____

Answer:

58 = Composite number.

Explanation:

Factors of 58:

1 × 58 = 58.

2 × 29 = 58.

Question 6.

23 _____

Answer:

23 = Prime number.

Explanation:

Factors of 23:

1 × 23 = 23.

Question 7.

Taylor said that if you multiply two prime numbers, the product is also a prime number. Do you agree? Why or why not?

Answer:

Yes, I agree with Taylor if you multiply two prime numbers, the product is also a prime number because there are infinitely many prime numbers, there are also infinitely many semiprimes.

Explanation:

In mathematics, a semiprime is a natural number that is the product of exactly two prime numbers. The two primes in the product may equal each other, so the semiprimes include the squares of prime numbers. Because there are infinitely many prime numbers, there are also infinitely many semiprimes.

Question 8.

Kayla asked her friends what season they liked best. 15 friends said summer. 11 friends said winter. 8 friends said spring. 4 friends said fall. Which season did a prime number of friends vote for?

Answer:

Winter season has a prime number of friends vote for because it has factors as itself and one.

Explanation:

Number of friends said summer season = 15.

Number of friends said winter season = 11.

Number of friends said spring season = 8.

Number of friends said fall season = 4.

Factors of 15:

1 × 15 = 15.

3 × 5 = 15.

Factors of 11:

1 × 11 = 11.

Factors of 8:

1 × 8 = 8.

2 × 4 = 8.

Factors of 4:

1 × 4 = 4.

2 × 2 = 4.