Question

Which of the following numbers will not have 6 at the unit's place in their squares?

• A. 35
• B. 23
• C. 64
• D. 76
• E. 94
• F. 42
• G. 98

Answer 1

Answer: (A), (B), (F), (G)

The correct options are
A 35
B 23
F 42
G 98

We know that when the unit place of a number is $4$ or $6$ then the square of that number has a unit place equal to $6$.

(A) Unit place of $(35{)}^2$ = Unit place of $5^2$ = 5
(B) Unit place of $(23{)}^2$ = Unit place of $3^2$ = 9
(C) Unit place of $(64{)}^2$ = Unit place of $4^2$ = 6
(D) Unit place of $(76{)}^2$ = Unit place of $6^2$ = 6
(E) Unit place of $(94{)}^2$ = Unit place of $4^2$ = 6
(F) Unit place of $(42{)}^2$ = Unit place of $2^2$ = 4
(G) Unit place of $(98{)}^2$ = Unit place of $8^2$ = 4

Hence, A, B, F, G are the correct answers.