Squaring numbers in the 50s
 Square the last digit (keep the carry) _ _ _ X
 Multiply the last digit by 10, add the carry _ _ X _
 The first digits will be 25 plus the carry: X X _ _
Example:
If the number to be squared is 53:
 Square the last digit (keep the carry):
3 × 3 = 9 (keep 3) _ _ _ 9
 Multiply the last digit by 10, add the carry:
10 × 3 = 30 (keep 3) _ _ 0 _
 The first digits will be 25 plus the carry:
25 (+ carry): 25 + 3 = 28 2 8 _ _
 So 53 × 53 = 2809.
See the pattern?
If the number to be squared is 56:
 Square the last digit (keep the carry):
6 × 6 = 36 (keep 3) _ _ _ 6
 Multiply the last digit by 10, add the carry:
10 × 6 = 60, 60 + 3 = 63 _ _ 3 _
 The first digits will be 25 plus the carry:
25 (+ carry): 25 + 6 = 31 3 1 _ _
 So 53 × 53 = 3136.
Practice and you will soon be producing these
products quickly and accurately.
