简便计算：1、5432.1×43.21-5432.2×43.20 2、4.74+（1.26-0.77） 3、3.85×6

1、5432.1×43.21-5432.2×43.20
=(5432+0.1)(43+0.21)-(5432+0.2)(43+0.2)
=5432*43+5432*0.21+43*0.1+0.1*0.21-5432*43-5432*0.2-43*0.2-0.2*0.2
=5432*(0.21-0.2)+43*(0.1-0.2)+0.021-0.04
=543.2-4.3-0.19
=538.71
2、4.74+（1.26-0.77）
=(4.74+1.26)-0.77
=6-0.77
=5.23
3、3.85×6.6+38.5×0.33+0.385
=38.5*(0.66+0.33)+0.385
=38.5*(1-0.01)+0.385
=38.5-0.385+0.385
=38.5
4、（4433-443.3）÷（8866-886.6）
=4433(1-0.1)/(8866(1-0.1))
=4433/8866
=1/2
再问： 你最后一题的1/2是什么意思啊！？
再答： 1/2=0.5