题目内容
简便计算.
3.68-
+6.32-
2.15×7.5+
×58.5
(
+
)×26×17.
3.68-
8 |
15 |
7 |
15 |
2.15×7.5+
3 |
4 |
(
2 |
13 |
2 |
17 |
考点:分数的简便计算
专题:运算定律及简算
分析:(1)两小数结合,两分数结合可使计算简便.
(2)7.5看作0.75乘10,把0.75化成分数
,应用乘法分配律可使计算简便.
(3)应用乘法分配律,用括号外的26×17分别乘括号内的,再求和.
(2)7.5看作0.75乘10,把0.75化成分数
3 |
4 |
(3)应用乘法分配律,用括号外的26×17分别乘括号内的,再求和.
解答:
解:(1)3.68-
+6.32-
=(3.68+6.32)-(
+
)
=10-1
=9;
(2)2.15×7.5+
×58.5
=21.5×
+
×58.5
=(21.5+58.5)×
=80×
=60;
(3)(
+
)×26×17
=
×26×17+
×26×17
=68+52
=120.
8 |
15 |
7 |
15 |
=(3.68+6.32)-(
8 |
15 |
7 |
15 |
=10-1
=9;
(2)2.15×7.5+
3 |
4 |
=21.5×
3 |
4 |
3 |
4 |
=(21.5+58.5)×
3 |
4 |
=80×
3 |
4 |
=60;
(3)(
2 |
13 |
2 |
17 |
=
2 |
13 |
2 |
17 |
=68+52
=120.
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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