试题

题目:
计算:
(1)4-(-4)+(-3);
(2)-7
1
3
+5+2
1
3

(3)-14-[3-(-2)3];
(4)(-
1
3
)×3÷(-3)×(-
1
3
)

(5)-2×(-2
1
6
)+(-7)×2
1
6
+5×
13
6

(6)4
1
2
×[-32×(-
1
3
)2-0.8]÷(-2
1
4
)

答案
解:(1)4-(-4)+(-3)
=4+4-3
=5;

(2)-7
1
3
+5+2
1
3

=-7
1
3
+2
1
3
+5
=-5+5
=0;

(3)-14-[3-(-2)3]
=-1-[3+8]
=-1-11
=-12;

(4)(-
1
3
)×3÷(-3)×(-
1
3
)

=-(
1
3
×
1
3
)×(3÷3)
=-
1
9
×1
=-
1
9


(5)-2×(-2
1
6
)+(-7)×2
1
6
+5×
13
6

=(2-7+5)×2
1
6

=0×2
1
6

=0;

(6)4
1
2
×[-32×(-
1
3
)2-0.8]÷(-2
1
4
)

=4
1
2
×[-9×
1
9
-0.8]×(-
4
9

=4
1
2
×[-1-0.8]×(-
4
9

=
9
2
×(-
9
5
)×(-
4
9

=
18
5

解:(1)4-(-4)+(-3)
=4+4-3
=5;

(2)-7
1
3
+5+2
1
3

=-7
1
3
+2
1
3
+5
=-5+5
=0;

(3)-14-[3-(-2)3]
=-1-[3+8]
=-1-11
=-12;

(4)(-
1
3
)×3÷(-3)×(-
1
3
)

=-(
1
3
×
1
3
)×(3÷3)
=-
1
9
×1
=-
1
9


(5)-2×(-2
1
6
)+(-7)×2
1
6
+5×
13
6

=(2-7+5)×2
1
6

=0×2
1
6

=0;

(6)4
1
2
×[-32×(-
1
3
)2-0.8]÷(-2
1
4
)

=4
1
2
×[-9×
1
9
-0.8]×(-
4
9

=4
1
2
×[-1-0.8]×(-
4
9

=
9
2
×(-
9
5
)×(-
4
9

=
18
5
考点梳理
有理数的混合运算.
(1)先化简,再相加即可求解;
(2)先算同分母分数,再相加即可求解;
(3)(6)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;
(4)运用乘法的交换律和交换律计算;
(5)运用乘法的分配律计算.
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-.
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