3/7+3/10÷7/15
=3/7+3/7*15/10
=3/7*(1+15/10)
=3/7*5/2
=15/14
3/10÷24/25÷3/8
=3/10÷3/8÷24/25
=8/10*25/24
=5/6
0.4÷(5/4×6/25)
=2/5÷(5/4×2/5*3/5)
=2/5÷2/5÷(5/4*3/5)
=1÷3/4
=4/3
3/7+3/10÷7/15=3/7+3/10*15/7=3/7*(1+15/10)=3/7*5/2=15/14
3/10÷24/25÷3/8=3/10*25/24*8/3=3/3*8/24*25/10=5/6
0.4÷(5/4×6/25)=2/5÷(5/4*6/25)=2/5*4/5*25/6=8/6=4/3
3/7+3/10÷7/15
=3/7+3/7×15/10
=3/7×(1+15/10)
=3/7×5/2
=15/14
3/10÷24/25÷3/8
=3/10÷3/8÷24/25
=8/10×25/24
=5/6
0.4÷(5/4×6/25)
=2/5÷(5/4×2/5×3/5)
=2/5÷2/5÷(5/4×3/5)
=1÷3/4
解:3/7+3/10÷7/15=3/7+3/7*15/10
=3/7*(1+15/10)
=3/7*5/2
=15/14
3/10÷24/25÷3/8=3/10÷3/8÷24/25
=8/10*25/24
=5/6
0.4÷(5/4×6/25)=2/5÷(5/4×2/5*3/5)
=2/5÷2/5÷(5/4*3/5)
=1÷3/4
=4/3谢谢