Browse · harp
Printjmc
number theory junior
Problem
The remainder when the product is divided by 5 is
(A)
(B)
(C)
(D)
(E)
Solution
To determine a remainder when a number is divided by , you only need to look at the last digit. If the last digit is or , the remainder is . If the last digit is or , the remainder is , and so on. To determine the last digit of , you only need to look at the last digit of each number in the product. Thus, we compute . The last digit of the number is also , and thus the remainder when the number is divided by is also , which gives an answer of .
Final answer
E