Assignment:
If you calculate 7^90 on a TI-83+ calculator, you will get 1.145047759x10^76. This is misleading since it implies that the digit in the ones place is zero. Explore powers of seven and use what you learn to determine what digit is in the ones place in the expansion of 7^90.
Note, this needs to be done without using a calculator more powerful than a TI-83+.
Provide complete and step by step solution for the question and show calculations and use formulas.