15÷9/10x3/5=15x10/9x3/5=150/9x3/5=10
15÷9/10×3/5＝15×3/5÷9/10＝9÷9/10＝9×10/9＝10
15÷(9/10)x(3/5)=15x(10/9)x(3/5)=15x(2/3)=10
