Multiplication Tricks
Multiplication of a number by 99
By using four simple steps and we can find result.
STEP 1: Insert a separator before the 10's digit of the multiplicant.
STEP 2: Add 1 to the number before the separator.
STEP 3: Subtract the output from the multiplicand which gives the left side answer.
STEP 4: Subtract the last digit[i.e after the separator of the multiplicant ] from 100.
Note : Only the leftmost part can have more than one digit. For the rest of the parts, we need to carry over the number preceding the units digit, to the immediate left part , and add it there respectively.
Lets see some examples:
Example 1: Find out 25 X 99.
STEP 1: __25 [Here __ is used for separator.]
STEP 2: 0+1=1
STEP 3: 25 -1 =24 [left side answer]
STEP 4: 100-25=75 [right side answer]
STEP 5: Combining the left side and right side together we will get our final result i.e 2475.
Example 2: Find out 334 X 99.
STEP 1: 3__34 [Here __ is used for separator.]
STEP 2: 3+1=4
STEP 3: 334 -4 =330 [left side answer]
STEP 4: 100-34=66 [right side answer]
STEP 5: Combining the left side and right side together we will get our final result i.e 33066.