题目内容
脱式计算(能简算的要简算).
|
|
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|
|
48×(
|
分析:(1)把除法改为乘法,再计算;
(2)把除法改为乘法,运用乘法分配律的逆运算简算;
(3)根据减法的性质,去括号,再运用加法交换律与结合律简算;
(4)按运算顺序计算,先算括号内的,再算括号外的;
(5)按运算顺序计算,先算
×
=
,云用加法结合律简算;
(6)根据数字特点,运用乘法分配律简算.
(2)把除法改为乘法,运用乘法分配律的逆运算简算;
(3)根据减法的性质,去括号,再运用加法交换律与结合律简算;
(4)按运算顺序计算,先算括号内的,再算括号外的;
(5)按运算顺序计算,先算
| 4 |
| 9 |
| 3 |
| 8 |
| 1 |
| 6 |
(6)根据数字特点,运用乘法分配律简算.
解答:解:(1)
÷
×5,
=
×
×5,
=
;
(2)
÷9+
×
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(3)
-(
+
),
=
-
-
,
=(
-
)-
,
=
-
,
=
;
(4)
×(
+
),
=
×(
+
),
=
×
,
=
;
(5)
+
×
+
,
=
+
+
,
=
+1,
=1
;
(6)48×(
+
-
),
=48×
+48×
-48×
,
=16+12-24,
=4.
| 1 |
| 7 |
| 2 |
| 3 |
=
| 1 |
| 7 |
| 3 |
| 2 |
=
| 15 |
| 14 |
(2)
| 6 |
| 25 |
| 6 |
| 25 |
| 8 |
| 9 |
=
| 6 |
| 25 |
| 1 |
| 9 |
| 6 |
| 25 |
| 8 |
| 9 |
=
| 6 |
| 25 |
| 1 |
| 9 |
| 8 |
| 9 |
=
| 6 |
| 25 |
=
| 6 |
| 25 |
(3)
| 11 |
| 12 |
| 1 |
| 9 |
| 5 |
| 12 |
=
| 11 |
| 12 |
| 1 |
| 9 |
| 5 |
| 12 |
=(
| 11 |
| 12 |
| 5 |
| 12 |
| 1 |
| 9 |
=
| 1 |
| 2 |
| 1 |
| 9 |
=
| 7 |
| 18 |
(4)
| 1 |
| 25 |
| 2 |
| 5 |
| 1 |
| 10 |
=
| 1 |
| 25 |
| 4 |
| 10 |
| 1 |
| 10 |
=
| 1 |
| 25 |
| 1 |
| 2 |
=
| 1 |
| 50 |
(5)
| 1 |
| 5 |
| 4 |
| 9 |
| 3 |
| 8 |
| 5 |
| 6 |
=
| 1 |
| 5 |
| 1 |
| 6 |
| 5 |
| 6 |
=
| 1 |
| 5 |
=1
| 1 |
| 5 |
(6)48×(
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 2 |
=48×
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 2 |
=16+12-24,
=4.
点评:此题重点考查学生对四则混合运算顺序的掌握情况,以及运用运算定律和性质简算的能力.
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