Find the last digit of 3^101 X 7^202

[cloveryeah]

Homework Statement

find the last digit of 3^101 X 7^202

Homework Equations

The Attempt at a Solution

i have cal. that the last digit is 7 by...:
[147]mod10 X ([3^4]mod10)^25 X ([7^4]mod10)^25 = [7]mod10 X [1]mod10 = [7]mod10
so the last digit is 7

is it correct?

 

[Dick]

Homework Statement

find the last digit of 3^101 X 7^202

Homework Equations

The Attempt at a Solution

i have cal. that the last digit is 7 by...:
[147]mod10 X ([3^4]mod10)^25 X ([7^4]mod10)^25 = [7]mod10 X [1]mod10 = [7]mod10
so the last digit is 7

is it correct?

Yes.