Question
Find the last two digits of the expression 84289?
Answer: Option C
:
C
84=21×4
The question changes to (21)289×4289
Using the last two digits technique for 1 -
For all numbers ending in 1, last digit is always 1.
Second last digit is the product of 10th digit of the base and the unit digit of the power.
E.g.
In this question 21289=__81
Using the last two digits technique based on the pattern of 2, we can arrive at the answer very fast.
4289=(22)289=2578=(210)57×28=__24×__56
Since, (210)odd power always ends in 24.
Answer =__81×__24×__56=__64
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:
C
84=21×4
The question changes to (21)289×4289
Using the last two digits technique for 1 -
For all numbers ending in 1, last digit is always 1.
Second last digit is the product of 10th digit of the base and the unit digit of the power.
E.g.
In this question 21289=__81
Using the last two digits technique based on the pattern of 2, we can arrive at the answer very fast.
4289=(22)289=2578=(210)57×28=__24×__56
Since, (210)odd power always ends in 24.
Answer =__81×__24×__56=__64
Was this answer helpful ?
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