Question

What is the right most non-zero digit of 270²⁷⁰ + 130¹³⁰?

Answer 1

$270^{270}=10^{270}\times 27^{270}$
$130^{130}=10^{130}\times 13^{130}$

That means $270^{270}$ ends with  $270$ zeroes and $130^{130}$  ends with $130$ zeroes . Notice that the right most non-zero digit is not affected by the first number. The problem reduces to finding the last digit of $13^{130}$ :

$13^{130}\equiv 3^{130}=9^{65}\equiv (-1)^{65}=-1\equiv 9\pmod{10}$

Therefore the last non-zero digit of $270^{270}+130^{130}$ is $9$