题目内容
计算.
(1)(+7.8)+(-6)+(-9
);
(2)(+4)+(-3
)+(-
)+(+3.5)+(-3
);
(3)(-2
)+(-3
)+(+5)+(+1.125)+(+4
).
(1)(+7.8)+(-6)+(-9
| 4 |
| 5 |
(2)(+4)+(-3
| 1 |
| 2 |
| 7 |
| 8 |
| 1 |
| 8 |
(3)(-2
| 1 |
| 8 |
| 1 |
| 2 |
| 1 |
| 2 |
(1)原式=[(+7.8)-9
]+(-6)
=(7.8-9.8)-6
=-2-6
=-8;
(2)原式=(+4)+[-3
+(+3.5)]+[(-
)+(-3
)]
=4-4
=0;
(3)原式=[-2
+(+1.25)]+[(-3
)+(+4
)]+(+5)
=-1+1+5
=5.
| 4 |
| 5 |
=(7.8-9.8)-6
=-2-6
=-8;
(2)原式=(+4)+[-3
| 1 |
| 2 |
| 7 |
| 8 |
| 1 |
| 8 |
=4-4
=0;
(3)原式=[-2
| 1 |
| 8 |
| 1 |
| 2 |
| 1 |
| 2 |
=-1+1+5
=5.
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