1.3824+2998
=3824+3000-2
=6824-2
=6822
2.6532-2999
=6532-3000+1
=3532-1
=3531
3.4.28/2.5/4
=4.28/(2.5*4)
=4.28/10
=0.428
4.125/（20/8）
=125*8/20
=1000/20
=50
5.3.2*1.02
=3.2*(1+0.02)
=3.2+0.064
=3.264
6.8.64-（1.64+3.5）
=8.64-1.64-3.5
=7-3.5
=3.5
7.2.4*3+2.4+2.4*6
=2.4*(3+1+6)
=2.4*10
=24