Explanation

• An irrational number cannot be expressed as a simple fraction.
• √2 is irrational because it cannot be expressed as a fraction of two integers.

Last verified on 16-06-2026

Explanation

• A number divisible only by 1 and itself is called a prime number.
• Prime numbers have only two factors.
• They cannot be divided evenly by any other number.
• 2 is the only even / smallest prime number.

Additional information:

• Numbers with more than 2 factors are called composite numbers.

Last verified 16-06-2026

Explanation

• 1, 3, 5, 7, 9 are odd numbers (فرد اعداد).
• Odd numbers are those which are not divisible by 2.
• They always end in 1, 3, 5, 7, or 9.
• They cannot be grouped equally in pairs.

Last verified on 16-06-2026

Explanation

( ) × 3 × 7 = 21  

( ) × 21 = 21  

So ( ) = 21 ÷ 21 = 1

Last verified on 16-06-2026

Explanation

• Odd numbers are integers that are not divisible by 2.
• They can be expressed in the form 2n + 1, where n is any integer.
• This formula always produces odd values like 1, 3, 5, 7, etc.

Last verified on 16-06-2026