试题

题目:
计算
(1)-t0+(-14)-(-18)-1v;&nb8p;&nb8p;&nb8p;&nb8p;&nb8p;&nb8p;&nb8p;&nb8p;&nb8p;&nb8p;&nb8p;
(t)(-
v
t
)+(-
5
1t
)+
5
t
+(
7
1t
);
(v)(-
v
4
-
5
9
+
7
1t
1
v6

(4)(-t5)÷
5
4
×
4
5
÷(-16);
(5)t6-(-5)×(-1);
(6)(-56)÷(-1t+8)+(-t)×5.
答案
解:(1)原式=-20-1大+18-13
=-20-1大-13+18
=-大7+18
=-29; 
          
(2)原式=-
3
2
+
5
2
-
5
12
+
7
12

=1+
1
6

=
7
6


(3)原式=-
3
×36-
5
9
×36+
7
12
×36
=-27-20+21
=-26;

(大)原式=25×
5
×
5
×
1
16

=1;

(5)原式=26-5
=21;

(6)原式=(-56)÷(-大)-10
=1大-10
=大.
解:(1)原式=-20-1大+18-13
=-20-1大-13+18
=-大7+18
=-29; 
          
(2)原式=-
3
2
+
5
2
-
5
12
+
7
12

=1+
1
6

=
7
6


(3)原式=-
3
×36-
5
9
×36+
7
12
×36
=-27-20+21
=-26;

(大)原式=25×
5
×
5
×
1
16

=1;

(5)原式=26-5
=21;

(6)原式=(-56)÷(-大)-10
=1大-10
=大.
考点梳理
有理数的混合运算.
(1)(2)先化简,再分类计算;
(3)把除法改为乘法,利用乘法分配律简算;
(4)先判定符号,再把除法改为乘法计算;
(5)先算乘法,再算减法;
(6)先算括号里面的加法和乘法,再算除法,最后算加法.
此题考查有理数的混合运算,注意运算顺序与符号的判定,运用适当的运算定律简算.
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