+126 You can start by doing 6x6, which is 36. If you multiply it by 6 again, the units digit is still six. So, the last digit is always going to be 6.
6^1 = 6
--------------- the stuff in between the two dash lines is one cycle of the pattern
6^2 = 36
6^3 = 216
6^4 = 1296 (by the way, for these you don't have to multiply the whole thing out, you just need to multiply the last two digits of each result by 6 until you see a pattern lol)
6^5 = 7776
6^6 = 46656
-----------------
6^7 = 279936
And yay! We've arrived back at the start of the pattern, with the tens digit being 3. There's 99 numbers from 2-100, and 99/5 is 19R4 and the 4th tens digit in the pattern cycle is 7.
So the last two digits are 7 and 6.
