31=3
32=9
33=27
34=81
35=243
...
So we conclude that 3 raised to any power divisible by 4 ends with a 1.
Similarly, 3 raised to any power "divisible by 4 minus one", such as 3, 7, 11, ... ends with a 7.
Can you figure out the answer for 3^59 (noting that 59=4*15-1)?
If 3 is raised to the 59th power, i.e. 359, what is the units digit? The units digit is the digit in the ones place. Explain the method used to find your answer.
1 answer