Respuestas

2013-07-23T01:19:40+02:00
ADICION HETEROGENEA:
3/4+4/3= 9/12+16/12 = 25/12
1/2+2/5= 5/10+4/10= 9/10
7/3+7/4= 28/12+21/12= 49/12
SUSTRACCION HETEROGENEA:
4/3-3/4= 16/12-9/12= 7/12
2-3/4= 8/4-3/4= 5/4
7/3-5/2=14/6-15/6 = -1/6
MULTIPLCACION 
7/3*7/5= 49/15
2/3*2/5=4/15
15/4*2/5= 30/20