fast calculation trick

multiple 99*56

now we can multiple 99 with any number an easy way like this
first we take 56 .
now we write 55 (one digit less than every number)
then we substract it also with 99 ie 99-55=44
so ans is 5544

multiple 999*545

similarly 
we first we take 545 
and we do one digit less from 545 ,so it is 543
and also substract 543 from 999 ,so it is 999-543=654
so ans is 543654

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