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Question 210205This question is from textbook impact mathematics
: what is the ones digits of the product of twenty-five threes? explain how you found your answer.
This question is from textbook impact mathematics
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! what is the ones digits of the product of twenty-five threes? explain how you found your answer.
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It's 3.
The least significant digit is cyclic, it goes:
exp LSD
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0....1
1....3
2....9
3....7
4....1
5....3
6....9
7....7
8....1
Every 4th power it's 1 (for all odd numbers except 5).
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So the 24th power it's 1, then it's a 3 for the 25th power.
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