Question

What is the last digit of $6^{109}$?

Answer 1

Consider,
$6^1=6$, last digit is 6.

$6^2=36$, last digit is 6.

$6^3=216$, last digit is 6.

$6^4=1296$, last digit is 6, and so on. [1 mark]

On generalizing, we get last digit in $6^{109}$ as 6.
[1 mark]