Medium
Which of the following is the unit place of 7^231?
Explanation
Explanation
Powers of 7 cycle through unit digits 7,9,3,1 with a cycle length of 4. 231 divided by 4 leaves remainder 3, corresponding to the 3rd term in the cycle, which is 3.
PRO TIP
Re-check your working by substituting the answer back into the original question.