题目内容
| 计算.(能简算的要简算) 14.4÷0.125÷8 | 1.5× |
| 920÷40+23×99 | |
| 1005÷[42×( | 35÷[1-( |
| 848-80÷16×27 | 29× |
解:
(1)14.4÷0.125÷8,
=14.4÷(0.125×8),
=14.4÷1,
=14.4;
(2)1.5×
+0.8×5.5+2×
,
=1.5×0.8+0.8×5.5+2×0.8,
=(1.5+5.5+2)×0.8,
=9×0.8,
=7.2;
(3)920÷40+23×99,
=23+23×99,
=23×(1+99),
=23×100,
=2300;
(4)
,
=(
)+(
),
=1+1,
=2;
(5)1005÷[42×(
)],
=1005÷[42×
-42×
)],
=1005÷[35-30],
=1005÷5,
=201;
(6)35÷[1-(
+
)],
=35÷[1-
],
=35÷
,
=35×
,
=
;
(7)848-80÷16×27,
=848-5×27,
=848-135,
=713;
(8)29×
×114,
=17×
+
×114,
=
×(17+114),
=
×131,
=29.
分析:(1)连续除以0.125与8,等于除以0.125与8的乘积,然后再进一步计算即可;
(2)
化成0.8,然后再根据乘法分配律进行简算即可;
(3)先计算920÷40=23,再根据乘法分配律进行简算即可;
(4)根据加法交换律和结合律进行简算即可;
(5)中括号内可以根据乘法分配律进行简算,然后再进一步计算即可;
(6)先计算小括号内的加法,再计算中括号内的减法,最后计算除法;
(7)先计算除法,再计算乘法,最后计算减法;
(8)根据分数乘整数的意义,可得29×
=17×
,然后再根据乘法分配律进行简算即可.
点评:能简便计算的,要灵活运用运算定律,然后再进一步进行计算,不能简便计算的,要按照运算顺序进行计算.
(1)14.4÷0.125÷8,
=14.4÷(0.125×8),
=14.4÷1,
=14.4;
(2)1.5×
=1.5×0.8+0.8×5.5+2×0.8,
=(1.5+5.5+2)×0.8,
=9×0.8,
=7.2;
(3)920÷40+23×99,
=23+23×99,
=23×(1+99),
=23×100,
=2300;
(4)
=(
=1+1,
=2;
(5)1005÷[42×(
=1005÷[42×
=1005÷[35-30],
=1005÷5,
=201;
(6)35÷[1-(
=35÷[1-
=35÷
=35×
=
(7)848-80÷16×27,
=848-5×27,
=848-135,
=713;
(8)29×
=17×
=
=
=29.
分析:(1)连续除以0.125与8,等于除以0.125与8的乘积,然后再进一步计算即可;
(2)
(3)先计算920÷40=23,再根据乘法分配律进行简算即可;
(4)根据加法交换律和结合律进行简算即可;
(5)中括号内可以根据乘法分配律进行简算,然后再进一步计算即可;
(6)先计算小括号内的加法,再计算中括号内的减法,最后计算除法;
(7)先计算除法,再计算乘法,最后计算减法;
(8)根据分数乘整数的意义,可得29×
点评:能简便计算的,要灵活运用运算定律,然后再进一步进行计算,不能简便计算的,要按照运算顺序进行计算.
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