1、（1/3+1/4-1/6）*24
=1/3x24+1/4x24-1/6x24
=8+6-4
=10
2、（-4）*（-5）*0.25
=4x0.25x5
=1x5
=5
3、100*（-3）*（-5）*0.01
=100x0.01x3x5
=1x15
=15