Solution:
We know that, the unit digit of the square of a natural number is the unit digit of the square of the digit at unit place of the given natural number.
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Now, we can find the unit digit of squares of the given numbers.
Unit digit of 432=9, because unit digit of 32 is 9.
Unit digit of 672=9, because unit digit of 72 is 9.
Unit digit of 522=4, because unit digit of 22 is 4.
Unit digit of 592=1, because unit digit of 92 is 1.
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Clearly the square of 592 ends with unit digit 1.
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