What is the unit digit of the product $243 \times 187 \times 56$?

Explanation

1. 01

   Only the unit digits matter: $3 \times 7 \times 6$.

2. 02

   $3 \times 7 = 21$, unit digit 1.

3. 03

   $1 \times 6 = 6$, so the unit digit is 6.