题目内容
计算(要写出计算过程) (-16)+(-8) | (-72)+(+63) | ||||||||||||||||
(-
| (-8)-(+4)+(-6)-(-1) | ||||||||||||||||
| 0-21
| ||||||||||||||||
[1.4-(-3.6+5.2)-4.3]-(-1.5) | 1-2+3-4+5-6+7-8+…+4999-5000 |
考点:正、负数的运算
专题:运算顺序及法则
分析:根据正、负数的加减运算方法,依次进行解答即可;其中最后一个:把相邻的两个数相减,可得2500个-1.即可求解.
解答:
解:(1)(-16)+(-8)
=-(16+8)
=-24
(2)(-72)+(+63)
=-72+63
=-(72-63)
=-9
(3)(-
)+
+0
=-(
-
)
=-
(4)(-8)-(+4)+(-6)-(-1)
=-8-4-6+1
=-17
(5)
-
-
+
=
+
-
-
=1-
-
=-
(6)0-21
+(+3
)-(-
)-(+
)
=-21
+3
+
-
=-21
+
+3
-
=-21+3
=-18
(7)[1.4-(-3.6+5.2)-4.3]-(-1.5)
=[1.4-1.6-4.3]+1.5
=[-0.2-4.3]+1.5
=-4.5+1.5
=-3
(8)1-2+3-4+5-6+7-8+…+4999-5000
=(1-2)+(3-4)+(5-6)+(7-8)+…+(4999-5000)
=(-1)+(-1)+(-1)+(-1)+…+(-1)
=-2500.
=-(16+8)
=-24
(2)(-72)+(+63)
=-72+63
=-(72-63)
=-9
(3)(-
1 |
2 |
1 |
3 |
=-(
1 |
2 |
1 |
3 |
=-
1 |
6 |
(4)(-8)-(+4)+(-6)-(-1)
=-8-4-6+1
=-17
(5)
1 |
3 |
1 |
2 |
3 |
4 |
2 |
3 |
=
1 |
3 |
2 |
3 |
1 |
2 |
3 |
4 |
=1-
1 |
2 |
3 |
4 |
=-
1 |
4 |
(6)0-21
2 |
3 |
1 |
4 |
2 |
3 |
1 |
4 |
=-21
2 |
3 |
1 |
4 |
2 |
3 |
1 |
4 |
=-21
2 |
3 |
2 |
3 |
1 |
4 |
1 |
4 |
=-21+3
=-18
(7)[1.4-(-3.6+5.2)-4.3]-(-1.5)
=[1.4-1.6-4.3]+1.5
=[-0.2-4.3]+1.5
=-4.5+1.5
=-3
(8)1-2+3-4+5-6+7-8+…+4999-5000
=(1-2)+(3-4)+(5-6)+(7-8)+…+(4999-5000)
=(-1)+(-1)+(-1)+(-1)+…+(-1)
=-2500.
点评:本题考查了正、负数的加减运算,正确理解运算法则是关键.
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