+0  
 
+1
38
1
avatar

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?

 Apr 5, 2022
 #1
avatar
+1

productfor(n, 1, 100, 7^n) mod 10^10 ==6696251249 - these are the last 10 digits.

 

4  x  9  ==36 - product of tens digit and ones digit.

 Apr 5, 2022

15 Online Users

avatar
avatar