题目内容
计算
(1)16
-(2
+3
)
(2)10÷[
-(
÷
+
)]
(3)
×[0.75-(
-0.25)]
(4)3
÷[5
-4.5×(20%+
)].
(1)16
| 3 |
| 7 |
| 2 |
| 5 |
| 3 |
| 7 |
(2)10÷[
| 8 |
| 3 |
| 5 |
| 13 |
| 5 |
| 26 |
| 2 |
| 5 |
(3)
| 4 |
| 7 |
| 7 |
| 16 |
(4)3
| 7 |
| 20 |
| 3 |
| 4 |
| 1 |
| 3 |
分析:(1)运用一个数减去两个数的和可以用这个数分别减去这两个数.
(2)、(4)按照分数的四则混合运算的顺序进行计算,有括号的先算括号内部的,再计算括号外面的.
(3)运用一个数减去两个数的差,可以用这个数减去被减数加上减数来进行计算会更加简便.
(2)、(4)按照分数的四则混合运算的顺序进行计算,有括号的先算括号内部的,再计算括号外面的.
(3)运用一个数减去两个数的差,可以用这个数减去被减数加上减数来进行计算会更加简便.
解答:解:(1)16
-(2
+3
),
=16
-3
-2
,
=13-2
,
=10
;
(2)10÷[
-(
÷
+
)],
=10÷[
-(
×
+
)],
=10÷[
-
],
=10÷[
-
],
=10÷
,
=10×
,
=32.5;
(3)
×[0.75-(
-0.25)],
=
×[0.75+0.25-
],
=
×
,
=
;
(4)3
÷[5
-4.5×(20%+
)],
=
÷[5
-4.5×
],
=
÷[
-
],
=
÷[
-
],
=
×
,
=
.
| 3 |
| 7 |
| 2 |
| 5 |
| 3 |
| 7 |
=16
| 3 |
| 7 |
| 3 |
| 7 |
| 2 |
| 5 |
=13-2
| 2 |
| 5 |
=10
| 3 |
| 5 |
(2)10÷[
| 8 |
| 3 |
| 5 |
| 13 |
| 5 |
| 26 |
| 2 |
| 5 |
=10÷[
| 8 |
| 3 |
| 5 |
| 13 |
| 26 |
| 5 |
| 2 |
| 5 |
=10÷[
| 8 |
| 3 |
| 12 |
| 5 |
=10÷[
| 40 |
| 15 |
| 36 |
| 15 |
=10÷
| 4 |
| 15 |
=10×
| 15 |
| 4 |
=32.5;
(3)
| 4 |
| 7 |
| 7 |
| 16 |
=
| 4 |
| 7 |
| 7 |
| 16 |
=
| 4 |
| 7 |
| 9 |
| 16 |
=
| 9 |
| 28 |
(4)3
| 7 |
| 20 |
| 3 |
| 4 |
| 1 |
| 3 |
=
| 67 |
| 20 |
| 3 |
| 4 |
| 8 |
| 15 |
=
| 67 |
| 20 |
| 23 |
| 4 |
| 12 |
| 5 |
=
| 67 |
| 60 |
| 115 |
| 20 |
| 48 |
| 20 |
=
| 67 |
| 60 |
| 20 |
| 67 |
=
| 1 |
| 3 |
点评:完成本题要注意分析算式中数据,运用合适的简便方法计算
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