题目内容
计算. 8470-104×65; |
0.6×(5.3-1.7)÷0.9; |
5.2÷0.8×6+42; |
÷(-)×; | [-(-)]÷. | ? |
解:(1)8470-104×65,
=8470-(100+4)×65,
=8470-100×65-4×65,
=8470-6500-260,
=1710;
(2)0.6×(5.3-1.7)÷0.9,
=0.6×3.6÷0.9,
=0.6×(3.6÷0.9),
=0.6×4,
=2.4;
(3)5.2÷0.8×6+42,
=39+42,
=81;
(4)÷(-)×,
=÷×,
=××,
=;
(5)[-(-)]÷,
=[-]÷,
=×,
=.
分析:(1)把104看作100+4,运用乘法分配律简算;
(2)先算括号内的,再算括号外的乘法和除法;
(3)先算除法和乘法,再算加法;
(4)先算括号内的,再算括号外的除法和乘法;
(5)先算小括号内的,再算中括号内的,最后算括号外的.
点评:此题重点考车四则混合运算的顺序以及计算能力.
=8470-(100+4)×65,
=8470-100×65-4×65,
=8470-6500-260,
=1710;
(2)0.6×(5.3-1.7)÷0.9,
=0.6×3.6÷0.9,
=0.6×(3.6÷0.9),
=0.6×4,
=2.4;
(3)5.2÷0.8×6+42,
=39+42,
=81;
(4)÷(-)×,
=÷×,
=××,
=;
(5)[-(-)]÷,
=[-]÷,
=×,
=.
分析:(1)把104看作100+4,运用乘法分配律简算;
(2)先算括号内的,再算括号外的乘法和除法;
(3)先算除法和乘法,再算加法;
(4)先算括号内的,再算括号外的除法和乘法;
(5)先算小括号内的,再算中括号内的,最后算括号外的.
点评:此题重点考车四则混合运算的顺序以及计算能力.
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