递等式计算（能简算的要简算）

7.6/（1.9*25）
=7.6/1.9*25
=4*25
=100
（2.5-1/1.25）*0.8
=(2.5-0.8)*0.8
=1.36
33.98-5.48-7.89-4.52
=26.09-10
=16.09
500+9.9*52=1014.8
(8.1-5.4)/3.6+85.7
=2.7+85.7
=88.4
5.4/(3.94+0.86)*0
=0