486-23乘以16
=486-368
=118；
2.5乘以3.2乘以1.25
=2.5×0.4×8×1.25
=1×10
=10；
3.5乘以2.6减4.5
=9.1-4.5
=4.6；
7减5分之4除以2减5分之3
=7-（4/5）÷2-3/5
=7-2/5-3/5
=7-(2/5+3/5)
=7-1
=6;
【1减【4分之1加8分之3】】除以4分之1
=(1-(1/4+3/8))×4
=4-4×(1/4)-4×(3/8)
=4-1-3/2
=3-3/2
=3/2;
24乘以【3分之1加6分之1减8分之3】
=24×(1/3)+24×(1/6)-24×(3/8)
=8+4-9
=3；
如果本题有什么不明白可以追问,