(1/6+1/9-1/12)÷4×9
=1/6*9/4+1/9*9/4-1/12*9/4
=3/8+1/4-3/16
=(6+4-3)/16
=7/16
3/20×3.4+5.6×0.15
=0.15*(3.4+5.6)
=0.15*(10-1)
=0.15*10-0.15*1
=1.5-0.15
=1.35
2.5-(3/5+2.4÷8/3)
=2.5-(0.6+0.9)
=2.5-1.5
=1
6/5/0.12+2.4*1/4=10+0.6=10.6
和是10.6
4*4+8=24
这个数是24