题目内容
脱式计算(带●的要简算)
| 13.25-18÷4.5+7.6 | 1÷[(
| ||||||||||||||
●
|
●
|
分析:(1)先算除法,再算减法和加法;
(2)把百分数变为分数,先算小括号内的,再算中括号内的,最后算括号外的;
(3)把除法改为乘法,运用乘法分配律简算;
(4)运用乘法分配律简算.
(2)把百分数变为分数,先算小括号内的,再算中括号内的,最后算括号外的;
(3)把除法改为乘法,运用乘法分配律简算;
(4)运用乘法分配律简算.
解答:解:(1)13.25-18÷4.5+7.6,
=13.25-4+7.6,
=9.25+7.6,
=16.85;
(2)1÷[(
-10%)÷
],
=1÷[(
-
)÷
],
=1÷[
×
],
=1÷
,
=1×30,
=30;
(3)
÷9+
×
,
=
×
+
×
,
=(
+
)×
,
=
×
,
=
;
(4)
×(
×
+
),
=
×
×
+
×
,
=
+1,
=1
.
=13.25-4+7.6,
=9.25+7.6,
=16.85;
(2)1÷[(
| 1 |
| 4 |
| 3 |
| 2 |
=1÷[(
| 1 |
| 4 |
| 1 |
| 5 |
| 3 |
| 2 |
=1÷[
| 1 |
| 20 |
| 2 |
| 3 |
=1÷
| 1 |
| 30 |
=1×30,
=30;
(3)
| 5 |
| 7 |
| 4 |
| 7 |
| 1 |
| 9 |
=
| 5 |
| 7 |
| 1 |
| 9 |
| 4 |
| 7 |
| 1 |
| 9 |
=(
| 5 |
| 7 |
| 4 |
| 7 |
| 1 |
| 9 |
=
| 9 |
| 7 |
| 1 |
| 9 |
=
| 1 |
| 7 |
(4)
| 6 |
| 5 |
| 2 |
| 9 |
| 6 |
| 5 |
| 5 |
| 6 |
=
| 6 |
| 5 |
| 2 |
| 9 |
| 6 |
| 5 |
| 5 |
| 6 |
| 6 |
| 5 |
=
| 8 |
| 25 |
=1
| 8 |
| 25 |
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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