Question

Match the following with the units digits in their squares.

• A. 4
• B. 6
• C. 9
• D. 1

Answer 1

The unit digit of a perfect square can only be 0, 1, 4, 5, 6 or 9.

The units digits of a number and the units digits of their squares pattern:

Numbers at units place	Numbers at units place of their squares
0	0
1 or 9	1
2 or 8	4
5	5
6 or 4	6
3 or 7	9

38 has 8 in its units place. So, its square ends with 4.

Similarly, for 24, 57 and 49.

• 24 has 4 in its units place. So, its square ends with 6.
• 57 has 7 in its units place. So, its square ends with 9.
• 49 has 9 in its units place. So, its square ends with 1.