递等式计算,能简便的用简便方法计算  4.4+5.6×2.5÷5.6×2.5               (3.8-7.7÷2.5)×2.8(7.5+7.5+7.5+7.5)×2.5             3.65×62+0.28×365+36.5(49.5÷7.5+49.5÷2.5)÷0.01 [3.25-3.25÷(10.3+2.2)]×0.1.

问题描述:

递等式计算,能简便的用简便方法计算  

4.4+5.6×2.5÷5.6×2.5               (3.8-7.7÷2.5)×2.8
(7.5+7.5+7.5+7.5)×2.5             3.65×62+0.28×365+36.5
(49.5÷7.5+49.5÷2.5)÷0.01 [3.25-3.25÷(10.3+2.2)]×0.1.

(1)4.4+5.6×2.5÷5.6×2.5
=4.4+(5.6÷5.6)×(2.5×2.5)
=4.4+1×6.25
=4.4+6.25
=10.65;
(2)(3.8-7.7÷2.5)×2.8
=(3.8-3.08)×2.8
=0.72×2.8
=2.016;
(3)(7.5+7.5+7.5+7.5)×2.5
=(7.5×4)×2.5
=7.5×(4×2.5)
=7.5×10
=75;
(4)3.65×62+0.28×365+36.5
=3.65×62+28×3.65+3.65×10
=3.65×(62+28+10)
=3.65×100
=365;
(5)(49.5÷7.5+49.5÷2.5)÷0.01
=(6.6+19.8)÷0.01
=26.4÷0.01
=2640;
(6)[3.25-3.25÷(10.3+2.2)]×0.1
=[3.25-3.25÷12.5]×0.1
=[3.25-0.26]×0.1
=2.99×0.1
=0.299.
答案解析:(1)先根据乘法交换律和乘法结合律把乘除法进行重新结合,最后再算加法;
(2)先算小括号里面的除法,再算小括号里面的减法,最后算括号外的乘法;
(3)先把小括号里面的加法变成乘法,再运用乘法结合律简算;
(4)先把算式变成各部分乘法都含有因数3.65的算式,再根据乘法分配律简算;
(5)先同时运算小括号里面的两个除法,再算小括号里面的加法,最后算括号外的除法;
(6)先算小括号里面的加法,再算中括号里面的除法,然后算中括号里面的减法,最后算括号外的乘法.
考试点:小数四则混合运算;运算定律与简便运算.
知识点:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.