The reciprocal of a number is another number which has a product of #1# when multiplied with the initial number. So if #ab=1# then #a# is the reciprocal of #b# and #b# is the reciprocal of #a#. For fractions, reversing the numerator and the denominator is a quick way to intuitively find the reciprocal. To do so with a calculator, simply divide #1# by the number you want to find the reciprocal of. Also, you can't divide by #0# so #0# is the reciprocal of no number (and likewise no number has a reciprocal equal to #0#)