题目内容
| 计算下面各题(能简算的要用简便方法算) 60×(
|
(
| ||||||||||||||
1-[
|
|
分析:采用乘法结合律、不同分母的分数相加减,先同分,再加减.结果要化成最简分数.
解答:解:60×(
+
-
),
=60×
+60×
-60×
,
=24+45-30,
=39;
(
+
)×
+
,
=
×
+
×
+
,
=
+
+
,
=
+1,
=1
;
1-[
+(
-
)],
=1-(
+
-
),
=1-
,
=
;
×
+
÷
,
=
×
+
×
,
=(
+
)×
,
=1
.
| 2 |
| 5 |
| 3 |
| 4 |
| 1 |
| 2 |
=60×
| 2 |
| 5 |
| 3 |
| 4 |
| 1 |
| 2 |
=24+45-30,
=39;
(
| 24 |
| 19 |
| 16 |
| 17 |
| 1 |
| 8 |
| 15 |
| 17 |
=
| 24 |
| 19 |
| 1 |
| 8 |
| 16 |
| 17 |
| 1 |
| 8 |
| 15 |
| 17 |
=
| 3 |
| 19 |
| 2 |
| 17 |
| 15 |
| 17 |
=
| 3 |
| 19 |
=1
| 3 |
| 19 |
1-[
| 1 |
| 6 |
| 3 |
| 4 |
| 7 |
| 12 |
=1-(
| 2 |
| 12 |
| 9 |
| 12 |
| 7 |
| 12 |
=1-
| 1 |
| 3 |
=
| 2 |
| 3 |
| 5 |
| 8 |
| 11 |
| 10 |
| 3 |
| 8 |
| 10 |
| 11 |
=
| 5 |
| 8 |
| 11 |
| 10 |
| 3 |
| 8 |
| 11 |
| 10 |
=(
| 5 |
| 8 |
| 3 |
| 8 |
| 11 |
| 10 |
=1
| 1 |
| 10 |
点评:此题考查了运算定律与简便运算和小数四则混合运算.分数四则混合运算同整数的四则混合运算相同,先算乘除,后算加减,有括号的先算括号.
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