试题

题目:
计算
(1)4-(-3)×(-1)-8×(-
1
2
)3×|-2-3|
 
(2)(-5)3×(-
3
5
)-32÷(-2)2×(+
5
4
)

(3)13+(+7)-(-20)-(-40)-(+6)
(4)(-7)-(+5)+(+3)-(-9)
(5)18-6÷(-2)×(-
1
3
)

(6)(-4)2×[-
3
4
+(-
5
8
)]

答案
解:(1)4-(-3)×(-1)-8×(-
1
2
)3×|-2-3|
 
=4-3+8×
1
8
×5
=4-3+5
=6;

(2)(-5)3×(-
3
5
)-32÷(-2)2×(+
5
4
)

=-125×(-
3
5
)-32÷4×
5
4

=75-10
=65;

(3)13+(+7)-(-20)-(-40)-(+6)
=13+7+20+40-6
=74;

(4)(-7)-(+5)+(+3)-(-9)
=-7-5+3+9
=-12+12
=0;

(5)18-6÷(-2)×(-
1
3
)

=18+3×(-
1
3

=18-1
=17;

(6)(-4)2×[-
3
4
+(-
5
8
)]

=16×(-
11
8

=-22.
解:(1)4-(-3)×(-1)-8×(-
1
2
)3×|-2-3|
 
=4-3+8×
1
8
×5
=4-3+5
=6;

(2)(-5)3×(-
3
5
)-32÷(-2)2×(+
5
4
)

=-125×(-
3
5
)-32÷4×
5
4

=75-10
=65;

(3)13+(+7)-(-20)-(-40)-(+6)
=13+7+20+40-6
=74;

(4)(-7)-(+5)+(+3)-(-9)
=-7-5+3+9
=-12+12
=0;

(5)18-6÷(-2)×(-
1
3
)

=18+3×(-
1
3

=18-1
=17;

(6)(-4)2×[-
3
4
+(-
5
8
)]

=16×(-
11
8

=-22.
考点梳理
有理数的混合运算.
(1)(2)(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;
(3)(4)先化简,再计算即可;
(5)按照有理数混合运算的顺序,先乘除后算加减,有括号的先算括号里面的.
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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