题目内容
计算下面各题,能简便的要用简便方法计算.
46×8-120%÷1.5
15+5÷(
-
)
÷
+
×
÷[(
+
)÷
].
46×8-120%÷1.5
15+5÷(
3 |
8 |
1 |
8 |
8 |
17 |
7 |
5 |
5 |
7 |
9 |
17 |
8 |
9 |
1 |
2 |
2 |
3 |
3 |
4 |
分析:(1)把百分数化为小数,先算乘除,再算减法;
(2)先算括号内的,再算除法,最后算加法;
(3)把除法改为乘法,运用乘法分配律简算;
(4)先算小括号内的,再算中括号内的,最后算括号外的.
(2)先算括号内的,再算除法,最后算加法;
(3)把除法改为乘法,运用乘法分配律简算;
(4)先算小括号内的,再算中括号内的,最后算括号外的.
解答:解:(1)46×8-120%÷1.5,
=368-1.2÷1.5,
=368-0.8,
=367.2;
(2)15+5÷(
-
),
=15+5÷
,
=15+20,
=35;
(3)
÷
+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(4)
÷[(
+
)÷
],
=
÷[
×
],
=
÷
,
=
×
,
=
.
=368-1.2÷1.5,
=368-0.8,
=367.2;
(2)15+5÷(
3 |
8 |
1 |
8 |
=15+5÷
1 |
4 |
=15+20,
=35;
(3)
8 |
17 |
7 |
5 |
5 |
7 |
9 |
17 |
=
8 |
17 |
5 |
7 |
5 |
7 |
9 |
17 |
=(
8 |
17 |
9 |
17 |
5 |
7 |
=1×
5 |
7 |
=
5 |
7 |
(4)
8 |
9 |
1 |
2 |
2 |
3 |
3 |
4 |
=
8 |
9 |
7 |
6 |
4 |
3 |
=
8 |
9 |
7 |
9 |
=
8 |
9 |
9 |
7 |
=
8 |
7 |
点评:考查了运算定律与简便运算,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律简便计算.
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