Question

列式计算：1/5+2/7÷3/7=？ 1/3÷（2/3-2/5）×3/5=? 5/9×3/10+2/7÷2/5=？

Answer 1

1/5+2/7÷3/7=？
1/5+2/7÷3/7=1/5+2/3=3/15+10/15=13/15
1/3÷（2/3-2/5）×3/5=?
1/3÷（2/3-2/5）×3/5=1/3÷4/15x3/5=1/3x15/4x3/5=3/4
5/9×3/10+2/7÷2/5=？
5/9×3/10+2/7÷2/5=1/6+5/7=37/42

Answer 2

1/5+2/7÷3/7=1/5 + 2/7×（7/3)=1/5 + 2/3=3/15 + 10/15=13/15
.
1/3÷（2/3-2/5）×3/5
=1/3 ×3/5÷（10/15 - 6/15)
=1/5 ÷（4/15)
=1/5 ×（15/4)
=3/4
.
5/9×3/10+2/7÷2/5
=1/6 + 5/7
=7/42 + 30/42
=37/42

Answer 3

十五分之十三
四分之三
四十二分之三十七

Answer 4

14×（4/7+1/2）÷3/2
=（14×4/7+14×1/2）×2/3
=15×2/3
=10
3÷3/5-3/5÷3
=5-1/5
=14/5
6/5×2/3-2/3×1/5
=4/5-2/15
=10/15=2/3
3/5+8×（7/8-5/6）
=3/5+7-20/3
=3/5+1/3
=14/15