Question

The square of a two-digit number has 8 in the units place.
How many two-digit numbers satisfy this property?
A. 1
8. 2
C. 3
D. (There is no two-digit number that satisfies this property.)
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Answer 1

D

Step-by-step explanation:

No 2-digit number can have in it's unit place.

$1^{2}=1\\2^{2}=4 \\3^{2}=9\\4^{2}=16$

Answer 2

There is no two-digit number that satisfies the property that their squares will have 8 in the units place (option D).

• The square of a number means to multiply a number twice. For example, the square of 2 will be 2×2 that is 4.
• The two-digit numbers are from 10 to 99. So, the digits on the unit place may be 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
• The squares of these 10 digits will be 0, 1, 4, 9, 16, 25, 36, 49, 64, and 81 respectively.
• We can easily see that 8 is not at the unit place for any number. So, in the two-digit or three-digit or any number for that matter, there can not be any number that has 8 at its unit place.