Respuesta :

Answer:

4/21

Step-by-step explanation:

4/21 can't be reduced anymore there is no number that goes into 4 and 21 and divides perfectly.

4/21 = 4/21

42/54 = 21/27 = 7/9

18/27 = 6/9 = 2/3

2/10 = 1/5