计算(能简算的要简算)32×0.25×12.5=10÷[-(÷+)]=12.85-1.17-8.83+1.15=÷[(+)÷]=75%×3.6+0.75×+=(20.

发布时间:2020-08-05 07:46:11

计算(能简算的要简算)
32×0.25×12.5=
10÷[-(÷+)]=12.85-1.17-8.83+1.15=÷[(+)÷]=75%×3.6+0.75×+=(20.2×0.4+7.88)÷4.2=

网友回答

解:(1)32×0.25×12.5,
=8×4×0.25×12.5,
=(8×12.5)×(4×0.25),
=100×1,
=100;

(2)10÷[-(÷+)],
=10÷[-(2+)],
=10÷[-],
=10÷,
=;

(3)12.85-1.17-8.83+1.15,
=(12.85+1.15)-(1.17+8.83),
=14-10,
=4;

(4)÷[(+)÷],
=÷[÷],
=÷,
=;

(5)75%×3.6+0.75×+,
=0.75×3.6+0.75×3.4+0.75×1,
=0.75×(3.6+3.4+1),
=0.75×8,
=6;

(6)(20.2×0.4+7.88)÷4.2,
=(8.08+7.88)÷4.2,
=15.96÷4.2,
=3.8.

解析分析:(1)先把32分解成8×4,再运用乘法结合律简算;
(2)先算小括号里面的除法,再算小括号里面的加法,然后算中括号里面的减法,最后算括号外的除法;
(3)运用加法结合律,以及连续减去两个数等于减去这两个数的和简算;
(4)先算小括号里面的加法,再算中括号里面的除法,最后算括号外的除法;
(5)先把分数、百分数化成小数,再运用乘法分配律简算;
(6)先算小括号里面的乘法,再算小括号里面的加法,最后算括号外的除法.

点评: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.
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