3/5÷6÷1/15
=3/5÷1/15÷6
=3/5x15÷6
=9÷6
=1.5
50×（3/10＋1/5）
=50×（3/10＋2/10）
=50×1/2
=25
3/8×4/7÷3/8×4/7
=3/8÷3/8×4/7×4/7
=1×4/7×4/7
=16/49
2/7÷8＋5/7×1/8
=2/7×1/8 ＋5/7×1/8
=(2/7+5/7)×1/8
=1×1/8
=1/8
15÷9/25×4/5
=15×4/5÷9/25
=12x25/9
=100/3
﹙13－3/10﹚÷3/5
=﹙130－3)/10x5/3
=127/10x5/3
=127/6