Question

Match the following cubes with their digits in the units place.

• A. 6
• B. 9
• C. 8
• D. 3

Answer 1

• If a number ends with 0, 1, 4, 5, 6, 9 then their cube also ends with the same number.

So, unit digit of ${36}^3$ is 6 and
unit digit of ${29}^3$ is 9

• But if the number ends with 2, then its cube ends with 8 and vice versa.

So, unit digit of ${42}^3$ is 8.

• Similarly, if the number ends with 3, then its cube ends with 7 and vice versa.

So, unit digit of ${117}^3$ is 3.