Sayantan Sir,

What is the unit's digit in the product 784 x 618 x 917 x 463?
Is there any special process to do so ? if there is please tell me how to do it.

1 Answers

269
Astha Gupta ·

it should be 2...
i did it in this way...I'll explain u with a simple example..
say...u wanna multiply...21 and 45...then..wat u usually do..???..
21
x45105
84x

--------
945
--------
so,if u carefully notice then u will find that the unit's digit
(the bold one's), always remains the same, since nothing is added to it.
so, by the same concept, just consider the unit's digit of all the four no.s, i.e.
4,8,7,3
now start multiplying them 1 by 1...
4x8=32...the unit's digit is 2
now multiplying 2 by 7..
2x7=14...the unit's digit is 4
now multiplying 4 by 3...
4x3=12
so,finally the units digit will be 2...
u may check it by actual division...u will get the same result..:)

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