NCERT Exemplar Solutions
Class 6 - Mathematics - Unit 1: Number System - Fill in the Blanks
Question 138

Question. 138

The number of factors of a prime number is ____.

Answer:

2

Detailed Answer with Explanation:

Step 1: What is a factor?

A factor of a number is a whole number that divides it exactly (no remainder).

We say \(a\) is a factor of \(n\) if:

\(n \div a\) leaves remainder \(0\).

Step 2: What is a prime number?

A prime number is a number greater than 1 that has only two different factors.

Those two factors are always:

\(1\) and the number itself.

Step 3: Example (Prime)

Take \(7\):

\(7 \div 1 = 7\)  →  exact, so \(1\) is a factor.

\(7 \div 7 = 1\)  →  exact, so \(7\) is a factor.

Try other numbers between 1 and 7:

\(7 \div 2\) is not exact,

\(7 \div 3\) is not exact,

… so there are no more factors.

Factors of \(7\): \(1, 7\) → total factors = \(2\).

Step 4: Compare (Not prime)

Take \(6\):

\(6 \div 1 = 6\), \(6 \div 2 = 3\), \(6 \div 3 = 2\), \(6 \div 6 = 1\).

Factors of \(6\): \(1, 2, 3, 6\) → total factors = \(4\) (so \(6\) is not prime).

Conclusion:

Every prime number has exactly two factors: \(1\) and itself.

NCERT Exemplar Solutions Class 6 – Mathematics – Unit 1: Number System – Fill in the Blanks | Detailed Answers