Speed Maths 1

A small post.

For Finding squares of numbers between 30-70

Say the number is 'X' and X is between 30 and 70.

Step 1: Find x-25.
X-25 will be the first digit/first 2 digits of the required answer.
Step 2:Find (50-X)^2
This will be the right most 2 digits.In case the square is a 3 digit number,
carry it over .

Example: 43
43-25
=18
50-43
=7
7 ^ 2 = 49
43 ^ 2 is 1849

Example 2:35
35-25=10
50-35=15
15 ^ 2 =225
Answer: 10, from 225 25 will be the 2 right most digits and carry over 2 to the 0 on the left side
So it becomes 1225.

Answer: 1225