Free Practice Question
PS · Problem Solving
sub-505
Exponents/Powers
What is the unit’s digit of 23^8?
Answer Choices
Correct answer marked below1
Correct
B
3
C
5
D
7
E
9
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Explanation
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Official Explanation
Official
The unit's digit of powers of 3 has a cyclicity of 4. The unit's digit for 3^1 is 3, for 3^2 is 9, for 3^3 is 7, and for 3^4 is 1. Since…
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Comments
2
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R
RhythmJan 10, 2025
how much time should this take to solve?
S
SameerMay 24, 2024
thank you very much!
What this question tests
What it tests
Your grasp of exponent rules — multiplying and dividing powers, power-of-a-power, and negative/zero exponents.
Common trap
Adding exponents when multiplying bases that have the same exponent, or confusing (x^a)^b with x^(a·b).
Details
Difficulty
sub-505
Type
PS
Category