When the expression (7^1)(7^2)(7^3) ... (7^100) is written as an integer, what is the product of the tens digit and the ones digit?

Guest Feb 8, 2022

#1**0 **

To find the power of the full expression, we can find the sum of the numbers from 1-100. So, using the Gauss Formula:

n(n+1)/2

100(101)/2

10100/2

5050

We can then find patterns, since we are trying to find the tens and ones digits.

7^1 = 07

7^2 = 49

7^3 = 343

7^4 = 2401

7^5 = 16807

7^6 = 11649

7^7 = 823543

Use the pattern to solve the answer. Hope this helps!

Let me know if I did anything wrong!

InhumanCalculator Feb 8, 2022