Countdown with scores. First, turn the fraction into a false fraction, then switch the numerator and denominator, which is the reciprocal of the number. In advanced mathematics, complex numbers also have reciprocal, for example, the reciprocal of I is-I.
In number theory,
There is also the concept of reciprocal number theory. If the product of two numbers A and B is 1 relative to the module M, then we call them the number theory reciprocal of the module M. 3 is the reciprocal of 2, is it about 5? The reciprocal of number theory is very important in China's remainder theorem. The alternate division provides a method to calculate the reciprocal of number theory.