Respuesta :

18 ÷ 3 = 6
21 ÷ 3 = 7

Answer: 6/7
18/21 in simplest form is 6/7

To find the simplest form, you have to find the GCF of 18 and 21 (which is i believe 3) and then divide both numbers by it.

(18/3)/(21/3) = 6/7