To expand on this method.
Take a number like 1230 10% of that number is 123.0 (found by shifting a decimal place) half of that is 61.5 add that to 123.0 =184.5 = 15%
To expand on this method.
Take a number like 1230 10% of that number is 123.0 (found by shifting a decimal place) half of that is 61.5 add that to 123.0 =184.5 = 15%