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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