题目内容
8 |
17 |
1 |
23 |
9 |
17 |
1 |
23 |
[5-(11.9-8.4)×1
1 |
3 |
3
7 |
20 |
3 |
4 |
1 |
3 |
2222×
27 |
100 |
分析:(1)把除法改为乘法,运用乘法分配律的逆运算简算;
(2)先算小括号内的,再算中括号内的乘法,然后算中括号内的减法,最后算括号外的除法;
(3)先算下括号内的,再算中括号内的乘法,然后算中括号内的减法,最后算括号外的除法;
(4)根据数字特点,把原式变为1111×2×0.27+1111×6×0.09-1111×3×0.16,运用乘法分配律的逆运算简算.
(2)先算小括号内的,再算中括号内的乘法,然后算中括号内的减法,最后算括号外的除法;
(3)先算下括号内的,再算中括号内的乘法,然后算中括号内的减法,最后算括号外的除法;
(4)根据数字特点,把原式变为1111×2×0.27+1111×6×0.09-1111×3×0.16,运用乘法分配律的逆运算简算.
解答:解:(1)
÷23+
×
+
,
=
×
+
×
+
,
=(
+
+1)×
,
=2×
,
=
;
(2)[5-(11.9-8.4)×1
]÷130%,
=[5-3.5×
]÷130%,
=[5-
×
]÷130%,
=[5-
]÷
=
×
,
=
;
(3)3
÷[5
-4.5×(20%+
)],
=3
÷[5
-4.5×(
+
)],
=3
÷[5
-4.5×
],
=3
÷[5
-
],
=
÷
,
=1;
(4)2222×
+6666×0.09-3333×0.16,
=1111×2×0.27+1111×6×0.09-1111×3×0.16,
=1111×(0.54+0.54-0.48),
=1111×0.6,
=666.6.
8 |
17 |
1 |
23 |
9 |
17 |
1 |
23 |
=
8 |
17 |
1 |
23 |
1 |
23 |
9 |
17 |
1 |
23 |
=(
8 |
17 |
9 |
17 |
1 |
23 |
=2×
1 |
23 |
=
2 |
23 |
(2)[5-(11.9-8.4)×1
1 |
3 |
=[5-3.5×
4 |
3 |
=[5-
7 |
2 |
4 |
3 |
=[5-
14 |
3 |
13 |
10 |
=
1 |
3 |
10 |
13 |
=
10 |
39 |
(3)3
7 |
20 |
3 |
4 |
1 |
3 |
=3
7 |
20 |
3 |
4 |
1 |
5 |
1 |
3 |
=3
7 |
20 |
3 |
4 |
8 |
15 |
=3
7 |
20 |
3 |
4 |
12 |
5 |
=
67 |
20 |
67 |
20 |
=1;
(4)2222×
27 |
100 |
=1111×2×0.27+1111×6×0.09-1111×3×0.16,
=1111×(0.54+0.54-0.48),
=1111×0.6,
=666.6.
点评:考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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