Đáp án:
Giải thích các bước giải:
Bai 1:
a;7/12+5/4=7/12+15/12=22/12
b;11/56-7/8=11/56-28/56=[1-11/56]-[1-28/56]=45/56-28/56=17/56
c;2/3+5/2-3/4=16/24+60/24-18/24=58/24
d;2/5*1/2:1/3=3/10:1/3=9/10
e;2/9:2/9*1/2=1*1/2=1/2
g;2/5*3/4*4/5:1/5=6/20*4/5:1/5=24/100:1/5=120/100
Bai 2:
a;[6/11+5/11]*3/7=1*3/7=3/7
b;[6/7-4/7]:2/5=2/7:2/5=10/14
Bai 3: