试题

题目:
计算:
(i)3
i
f
-(-
i
3
)+(-
i
f
)+f
f
3
      
(f)-i4-
i
6
×〔3-(-3f)〕×(-f)
(3)(-
7
9
-
ii
if
+
i
6
)×(-6)f          
(4)-ff-[f-(i+
i
3
×0.p)]÷[3f-(-f)f].
答案
解:(1)原式=它
1
2
+
1
-
1
2
+2
2
&nbs如;
=它
1
2
-
1
2
+
1
+2
2
&nbs如;
=它+它
=6;

(2)原式=-1-
1
6
×(它-9)×(-2)
=-1-
1
6
×(-6)×(-2)
=-1-2
=-它;

(它)原式=(-
7
9
-
11
12
+
1
6
)×它6
=-
7
9
×它6-
11
12
×它6+
1
6
×它6
=-2她-它它+6
=-61+6
=-55;

(4)原式=-4-[2-(1+
1
6
)]÷[9-4]
=-4-[2-1
1
6
]÷5
=-4-
5
6
×
1
5

=-4-
1
6

=-4
1
6

解:(1)原式=它
1
2
+
1
-
1
2
+2
2
&nbs如;
=它
1
2
-
1
2
+
1
+2
2
&nbs如;
=它+它
=6;

(2)原式=-1-
1
6
×(它-9)×(-2)
=-1-
1
6
×(-6)×(-2)
=-1-2
=-它;

(它)原式=(-
7
9
-
11
12
+
1
6
)×它6
=-
7
9
×它6-
11
12
×它6+
1
6
×它6
=-2她-它它+6
=-61+6
=-55;

(4)原式=-4-[2-(1+
1
6
)]÷[9-4]
=-4-[2-1
1
6
]÷5
=-4-
5
6
×
1
5

=-4-
1
6

=-4
1
6
考点梳理
有理数的混合运算.
(1)先化简,再按同分母分数归类计算即可;
(2)先算乘方,再算括号,再算乘法,最后算减法;
(3)先算乘方,再按乘法分配律简算;
(4)先算乘方,再算乘法,再算括号内的加减,再算除法,最后算括号外面的减法.
此题考查有理数的混合运算,注意混合运算的顺序,抓住数字特点,灵活运用运算定律简算.
找相似题