题目内容
脱式计算: (124-85)×12÷26 |
(75+360)÷(20-5) | 19.92+14.4-9.92 |
85.7-(15.3-4.8) | 9.5+4.85-6.13 | 40-(2.75+0.86) |
分析:(1)先算小括号里面的减法,再算括号外的乘法,最后算除法.
(2)先同时运算小括号里面的加法和减法,再算括号外的除法;
(3)运用加法交换律简算;
(4)先算小括号里面的减法,再算括号外的减法;
(5)按照从左到右的顺序计算;
(6)先算小括号里面的加法,再算括号外的减法.
(2)先同时运算小括号里面的加法和减法,再算括号外的除法;
(3)运用加法交换律简算;
(4)先算小括号里面的减法,再算括号外的减法;
(5)按照从左到右的顺序计算;
(6)先算小括号里面的加法,再算括号外的减法.
解答:解:(1)(124-85)×12÷26,
=39×12÷26,
=468÷26,
=18;
(2)(75+360)÷(20-5),
=435÷15,
=29;
(3)19.92+14.4-9.92,
=19.92-9.92+14.4,
=10+14.4,
=24.4;
(4)85.7-(15.3-4.8),
=85.7-10.5,
=75.2;
(5)9.5+4.85-6.13,
=14.35-6.13,
=8.22;
(6)40-(2.75+0.86),
=40-3.61,
=36.39.
=39×12÷26,
=468÷26,
=18;
(2)(75+360)÷(20-5),
=435÷15,
=29;
(3)19.92+14.4-9.92,
=19.92-9.92+14.4,
=10+14.4,
=24.4;
(4)85.7-(15.3-4.8),
=85.7-10.5,
=75.2;
(5)9.5+4.85-6.13,
=14.35-6.13,
=8.22;
(6)40-(2.75+0.86),
=40-3.61,
=36.39.
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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