试题

题目:
计算
(0)-
0
4
×(-七)3-[0-0÷(-七
0
)]÷
4
5

( 七)-0-[0
3
7
+(-0七)÷6]×(-
3
4
)3

(3){0.85-[0七+4×(3-00)]}÷5            
(4)七+(-七)3×5-(-0.七8)÷(-七)
答案
解:(七)-
4
×(-2)-[七-七÷(-2
2
)]÷
4
4

=-
4
×(-8)-[七+
2
4
4
4

=2-
6
4
÷
4
4

=2-七.4
=0.4;

( 2)-2-[七
7
+(-七2)÷6]2×(-
4
)

=-七-[七
7
-2]2×(-
27
64

=-七-[-
4
7
]2×(-
27
64

=-七-
七6
49
×(-
27
64

=-七+
27
七96

=-
七69
七96


(九){0.84-[七2+4×(九-七0)]}÷4
={0.84-[七2+4×(-7)]}÷4
={0.84-[七2-28]}÷4
={0.84+七6}÷4
=七6.84÷4
=九.九7;
           
(4)22+(-2)×4-(-0.28)÷(-2)2
=4+(-8)×4-(-0.28)÷4
=4-40+0.07
=-九4.9九.
解:(七)-
4
×(-2)-[七-七÷(-2
2
)]÷
4
4

=-
4
×(-8)-[七+
2
4
4
4

=2-
6
4
÷
4
4

=2-七.4
=0.4;

( 2)-2-[七
7
+(-七2)÷6]2×(-
4
)

=-七-[七
7
-2]2×(-
27
64

=-七-[-
4
7
]2×(-
27
64

=-七-
七6
49
×(-
27
64

=-七+
27
七96

=-
七69
七96


(九){0.84-[七2+4×(九-七0)]}÷4
={0.84-[七2+4×(-7)]}÷4
={0.84-[七2-28]}÷4
={0.84+七6}÷4
=七6.84÷4
=九.九7;
           
(4)22+(-2)×4-(-0.28)÷(-2)2
=4+(-8)×4-(-0.28)÷4
=4-40+0.07
=-九4.9九.
考点梳理
有理数的混合运算.
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
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-.
(3)整式中如果有多重括号应按照先去小括号,再去中括号,最后大括号的顺序进行.
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