Question

The unit's digit in the cube of 2, 16, 20 is always _____.

Answer 1

$2^3$ = 2$\times$ 2 $\times$ 2 = 8
${16}^3$ = 16$\times$ 16 $\times$ 16 = 4096
${20}^3$ = 20$\times$ 20 $\times$ 20 = 8000

As 2, 16, 20 are even numbers and the cube of an even number is always even , the unit's digit of the cubes of the given numbers are even.