题目内容
计算
(1)(-38)+52+118+(-62)
(2)(-3
)-(-2
)-(-1
)-(+1.75)
(3)|-
|÷(
-
)-
×(-4)2
(4)-22÷
-[22-(1-
×
)]×12.
(1)(-38)+52+118+(-62)
(2)(-3
2 |
3 |
3 |
4 |
2 |
3 |
(3)|-
7 |
9 |
2 |
3 |
1 |
5 |
1 |
3 |
(4)-22÷
4 |
3 |
1 |
2 |
1 |
3 |
分析:(1)根据加法交换率和结合律计算即可求解;
(2)先算同分母分数,再相加即可求解;
(3)(4)按照有理数混合运算的顺序,先乘方后乘除最后算加减,有括号的先算括号里面的.
(2)先算同分母分数,再相加即可求解;
(3)(4)按照有理数混合运算的顺序,先乘方后乘除最后算加减,有括号的先算括号里面的.
解答:解:(1)(-38)+52+118+(-62)
=(-38-62)+(52+118)
=-100+170
=70;
(2)(-3
)-(-2
)-(-1
)-(+1.75)
=(-3
+1
)+(2.75-1.75)
=-1+1
=0;
(3)|-
|÷(
-
)-
×(-4)2
=
÷
-
×16
=
-
=-3
;
(4)-22÷
-[22-(1-
×
)]×12
=-4÷
-[4-(1-
)]×12
=-3-[4-
]×12
=-3-
×12
=-3-38
=-41.
=(-38-62)+(52+118)
=-100+170
=70;
(2)(-3
2 |
3 |
3 |
4 |
2 |
3 |
=(-3
2 |
3 |
2 |
3 |
=-1+1
=0;
(3)|-
7 |
9 |
2 |
3 |
1 |
5 |
1 |
3 |
=
7 |
9 |
7 |
15 |
1 |
3 |
=
5 |
3 |
16 |
3 |
=-3
2 |
3 |
(4)-22÷
4 |
3 |
1 |
2 |
1 |
3 |
=-4÷
4 |
3 |
1 |
6 |
=-3-[4-
5 |
6 |
=-3-
19 |
6 |
=-3-38
=-41.
点评:本题考查的是有理数的运算能力.注意:
(1)要正确掌握运算顺序,在混合运算中要特别注意运算顺序:先三级,后二级,再一级;有括号的先算括号里面的;同级运算按从左到右的顺序;
(2)去括号法则:--得+,-+得-,++得+,+-得-.
(1)要正确掌握运算顺序,在混合运算中要特别注意运算顺序:先三级,后二级,再一级;有括号的先算括号里面的;同级运算按从左到右的顺序;
(2)去括号法则:--得+,-+得-,++得+,+-得-.
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