What is the reciprocal of #3#?
Taking the reciprocal of a number means to "flip" the number or take 1 over that value:
The numerator becomes the denominator and the denominator becomes the numerator.
From what you've given me, 3 is the numerator and 1 is the denominator. The 1 is implied so it doesn't have to be written.
When we flip that number, the numerator which was 3 now becomes the denominator and it is placed on the bottom; the denominator which was 1, is now the numerator and is placed on top of the 3:
I hope this makes sense!