题目内容
脱式计算
(1)3034-630÷18+1003
(2)(
+
)×
+
(3)0.56÷1.4×(5-0.75)
(4)(
+10×
)÷
(5)7.5÷[(
-
)×
].
(1)3034-630÷18+1003
(2)(
| 5 |
| 12 |
| 5 |
| 16 |
| 4 |
| 5 |
| 7 |
| 12 |
(3)0.56÷1.4×(5-0.75)
(4)(
| 14 |
| 15 |
| 4 |
| 15 |
| 9 |
| 25 |
(5)7.5÷[(
| 2 |
| 3 |
| 4 |
| 7 |
| 7 |
| 8 |
分析:(1)先算除法,再算减法,最后算加法,
(2)运用乘法的分配律进行计算,再从左到右进行计算,
(3)先算括号里的减法,再从左到右进行计算,
(4)先算括号里的乘法,再算加法,最后算括号外的除法,
(5)先运用乘法分配律简算中括号里的乘法,最后算括号外的除法.
(2)运用乘法的分配律进行计算,再从左到右进行计算,
(3)先算括号里的减法,再从左到右进行计算,
(4)先算括号里的乘法,再算加法,最后算括号外的除法,
(5)先运用乘法分配律简算中括号里的乘法,最后算括号外的除法.
解答:解:(1)3034-630÷18+1003,
=3034-35+1003,
=2999+1003,
=4002;
(2)(
+
)×
+
,
=
×
+
×
+
,
=
+
+
,
=
+
,
=
;
(3)0.56÷1.4×(5-0.75),
=0.56÷1.4×4.25,
=0.4×4.25,
=1.7;
(4))(
+10×
)÷
,
=(
+10×
)÷
,
=(
+
)÷
,
=
÷
,
=10;
(5)7.5÷[(
-
)×
],
=7.5÷[
×
-
×
],
=7.5÷[
-
],
=7.5÷
,
=90;
=3034-35+1003,
=2999+1003,
=4002;
(2)(
| 5 |
| 12 |
| 5 |
| 16 |
| 4 |
| 5 |
| 7 |
| 12 |
=
| 5 |
| 12 |
| 4 |
| 5 |
| 5 |
| 16 |
| 4 |
| 5 |
| 7 |
| 12 |
=
| 1 |
| 3 |
| 1 |
| 4 |
| 7 |
| 12 |
=
| 7 |
| 12 |
| 7 |
| 12 |
=
| 7 |
| 6 |
(3)0.56÷1.4×(5-0.75),
=0.56÷1.4×4.25,
=0.4×4.25,
=1.7;
(4))(
| 14 |
| 15 |
| 4 |
| 15 |
| 9 |
| 25 |
=(
| 14 |
| 15 |
| 4 |
| 15 |
| 9 |
| 25 |
=(
| 14 |
| 15 |
| 40 |
| 15 |
| 9 |
| 25 |
=
| 54 |
| 15 |
| 9 |
| 25 |
=10;
(5)7.5÷[(
| 2 |
| 3 |
| 4 |
| 7 |
| 7 |
| 8 |
=7.5÷[
| 2 |
| 3 |
| 7 |
| 8 |
| 4 |
| 7 |
| 7 |
| 8 |
=7.5÷[
| 7 |
| 12 |
| 1 |
| 2 |
=7.5÷
| 1 |
| 12 |
=90;
点评:考查了整数、小数、分数四则混合运算顺序,灵活运用运算定律进行简算.
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