what is the unit digit of N if N = (289)5 *(587)7 *(1156)9 *(17)15 without actual multiplying
A.8
B.5
C.3
D.6
show me how to do this 1 step by step
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3 Answers
21this might help you -http://www.goiit.com/posts/list/community-shelf-to-solve-last-digit-problems-993265.htm
1the powers follow a pattern
9^1=9
9^2=81..last dig:1
. .
.
.
^5=9
silimilarly
for 7
7^7=3...(last digit)
for6=6
now multiply:7*3*6*3=6 last digit ans
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