大家好，我是小环，我来为大家解答以上问题。五年级简算数学题，五年级简算很多人还不知道，现在让我们一起来看看吧！

1、 7.5*3.1/2.5*100 =7.5/2.5*3.1*100 =3*3100 =9300 2、36.5*6.2+28*0.365+3.65 =36.5*6.2+2.8*3.65+3.65 =3.65*（6.2+2.8+1） =3.65*1. =36.5 3、999.9*599.9+199.9 =1000×599+0.1×599.9+200-0.1 =5990+59.9+200-0.1 =6049.9+200-0.1 =6249.9-0.1 =6249.8 999.9*599.9+199.9 =(1000-0.1)*599.9+(200-0.1) =1000*599.9-0.1*599.9+200-0.1 =599900-599.99+200-0.1 =599900-(600-0.1)+200-0.1 =599900-600+0.1+200-0.1 =599900-600+200 =599500 999.9X599.9+199.9 =(1000-0.1)X599.9+(200-0.1) =1000X599.9-0.1X599.9+200-0.1 =599900-59.99+200-0.1 =599900-(60-0.01)+200-0.1 =599900-60+0.01+200-0.1 =599900+200+0.01-60-0.1 =600039.91 999.9×599.9+199.9 = （1000－0．1）×599.9+199.9 ＝1000×599.9－0.1×599.9+199.9 ＝599900－59.9+199.9 ＝599900＋140 ＝60040 自己看一下哪个对吧。

2、看我那么辛苦。

3、给分吧~~~~~~~~。

本文到此讲解完毕了，希望对大家有帮助。