Find the remainder when 7[50k-1] is divided by 50
7[50k - 1] = 7[50k - 1 - 49] + 7 × 49 (we add and subtract 7 * 49)
= 7[50k - 50] + 300 + 43
The first two terms are multiple of 50
⇒ The remainder will be 43
What is the remainder when 7103 is divided by 50?
Find the remainder when (1+8)n+7 is divided by 8