Units digit of a large number: ACT Math Practice Question

Try this ACT math practice question that tests your ability to recognize a pattern in units digits of large powers of an integer.

The units digit(the digit in the one’s place of a number) of $7^{77}$ is $7$. What is the units digit of $7^{80}$?

1. $\quad 0$
2. $\quad 1$
3. $\quad 3$
4. $\quad 7$
5. $\quad 9$

Choice B

Video explanation