respuesta
1. 23/35
2. 5/9
3 9/13
4 2/21
esplicacion paso a paso
4/5-1/7 =
28-5 = 23/35
2/3_1/9 =
18-3=15/27= 5/9
5/6_1/12=
30-3=27/36 = 9/12
1/7-2/21 =
3_1= 1/21
