Squaring numbers in the 20s Square the last digit (keep the carry) _ _ X Multiply the last digit by 4, add the carry _ X _ The first digit will be 4 plus the carry: X _ _ Example: If the number to be squared is 24: Square the last digit (keep the carry): 4 × 4 = 16 (keep 1) _ _ 6 Multiply the last digit by 4, add the carry: 4 × 4 = 16, 16 + 1 = 17 _ 7 _ The first digit will be 4 plus the carry: 4 (+ carry): 4 + 1 = 5 5 _ _ So 24 × 24 = 576. See the pattern? If the number to be squared is 26: Square the last digit (keep the carry): 6 × 6 = 36 (keep 3) _ _ 6 Multiply the last digit by 4, add the carry: 4 × 6 = 24, 24 + 3 = 27 (keep 2) _ 7 _ The first digit will be 4 plus the carry: 4 (+ carry): 4 + 2 = 6 6 _ _. So 26 × 26 = 676.
							
Squaring numbers in the 20s

Square the last digit (keep the carry)   _ _ X

Multiply the last digit by 4, add the carry   _ X _

The first digit will be 4 plus the carry:   X _ _



   Example:

     If the number to be squared is 24:

Square the last digit (keep the carry): 

    4 × 4 = 16 (keep 1)     _ _ 6

Multiply the last digit by 4, add the carry:

    4 × 4 = 16, 16 + 1 = 17    _ 7 _

The first digit will be 4 plus the carry: 

    4 (+ carry): 4 + 1 = 5    5 _ _

So 24 × 24 = 576.



   See the pattern?

     If the number to be squared is 26:

Square the last digit (keep the carry): 

    6 × 6 = 36 (keep 3)    _ _ 6

Multiply the last digit by 4, add the carry:

    4 × 6 = 24, 24 + 3 = 27 (keep 2)   _ 7 _

The first digit will be 4 plus the carry: 

    4 (+ carry): 4 + 2 = 6  6 _ _.

So 26 × 26 = 676.