Question

If the square ends with 1, then the number has ___ or ___ in the units place.

• A. $3$ or $7$
• B. $4$ or $6$
• C. $2$ or $8$
• D. $1$ or $9$

Answer 1

The correct option is D $1$ or $9$

For example, $11\times 11=12\underset{–}{1}$
$19\times 19=36\underset{–}{1}$ ( square ends with 1)
Therefore, D is the correct answer.