24*（5/8+5/6）
=24*5/8+24*5/6
=15+20
=35
1.25*16
=1.25*8*2
=10*2
=20
1705+450÷18*32
=1705+50÷2*32
=1705+50*16
=1705+800
=2505
3/5÷6/25*2/9
=3/5*25/6*2/9
=1/5*25*1/9
=5*1/9
=5/9