There are many tricks for multiplication . out of all the tricks you need to decide which would be applicable while simplifying questions. Practicing questions while make you quick in understanding which trick is to be applied for quickly solving it.
Now this trick is useful when you find that multiplier is number having all digits 9.
Example : 9,99,999,9999 all such number if are multiplier than this trick is to be used.
Let us now check few examples.
Case 1: Here multiplier and multiplicand are having equal number of digits.
1) 4 * 9 (both multiplier and multiplicand are single digit number.)
here 9 is multiplier and 4 is multiplicand.
Trick : take multiplicand and subtract one from it. => 4-1
find out complement of the multiplicand or subtract multiplicand from 10 => 10-4=6
=> 4-1/6
=>36
Answer is 36.
2) 35 * 99
multiplier here is 99 and multiplicand is 35
Trick:
- 35-1 =34
- 100-35=65( compliment of 35 or subtraction of 35 from 100.)
so , 3465
Answer : 3465.
3) 619 *999
multiplier here is 999 and multiplicand is 619.
Trick :
- 619-1 = 618
- 1000-619 =381
so, 618381
Answer : 618381.
Now keep on practicing such multiplication
6195 *9999 = 61943805
3422 *9999= 34216578
5321*9999=53204679
44792*99999= 4479155208
654123*999999=654122345877
Any big number can be multiplied without even writing anything on paper
Note : To find compliment of big numbers : e.g. to find compliment of 654123
Each term is to be subtracted from 10 (10-6) , then subtract 1 from result , only in last digit is to be subtracted only from 10, the result after subtracting from 10 is final for last digit only.
Answer : 3458777
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