To multiply a number by 5
Step 1: Divide by 2
Step 2: Move the decimal point to the right. (Multiply by 10)
For example: 1450x5
Step 1: 1450/2 ==> 725
Step 2: 725x10==> 7250 Ans.
squaring a two digit number that begins with a '5'
1-square the first digit
2-add this number to the second number to find the first part of the answer
3-square the second digit: that is the last part of the answer.
Example:what is the square of 58==> 58^2?
5^2=25==>25+8=33 _ _
8^2=64==> 3364Ans.
