Respuesta :

Divide it by the greatest common factor.  In this case, it is 7.  21 divided by 7 is 3 and 56 divided by 7 is 8.  21/56 in simplest form is 7/8.
The GCF is 7.

Therefore, divide both denominator and numerator by 7.

21 ÷ 7
56 ÷ 7

= 3/8