Đáp án:
Giải thích các bước giải:
a)7/9 + 9/10=70/90+81/90=151/90
b) 3/5 + 1/2 - 3/10=6/10+5/10-3/10=8/10=4/5
c) 7/9 x 4/5=28/45
d) 1/5 : 7/8=1/5 x 8/7=8/35
e) 1/10 - 3/4=2/20-15/20=-13/20
f) 15/16 : 3/8 x 3/4=15/16 x 8/3 x 3/4=15/16 x 2=15/8
g) 3/5 + 6/11 + 7/13 + 2/5 + 16/11 + 19/13=(3/5+2/5)+(6/11+16/11)+(7/13+19/13)=5/5+22/11+26/13
=1+2+2=5
Chúc bạn học tốt!!