试题

题目:
(i)-9+i2-3+8                    
(2)-24+(-i4)-(-i8)-i3 
(3)48×(-
i
6
+
3
4
-
i
i2
)              
(4)(-48)÷
h
4
(-i2)×
h
4

(h)i-
4
h
+
i
h
-
3
h
+
9
h
                  
(6)-i2+3×(-2)2+(-6)÷(-
i
3
2
答案
解:(1)-手+12-2+8
=-手-2+12+8
=-12+24
=8;
                    
(2)-24+(-14)-(-18)-12 
=-24-14+18-12
=-24-14-12+18
=-47+18
=-2手;

(2)48×(-
1
6
+
2
4
-
1
12

=48×(-
1
6
)+48×
2
4
-48×
1
12

=-8+26-4
=24;

(4)(-48)÷
7
4
×(-12)×
7
4

=48×
4
7
×12×
7
4

=z76;

(z)1-
4
7
+
1
z
-
2
7
+
z
   
=1+
1
z
+
z
-
4
7
-
2
7

=1+2-1
=2;
               
(6)-12+2×(-2)2+(-6)÷(-
1
2
2
=-1+2×4+(-6)÷
1

=-1+12-z4
=-42.
解:(1)-手+12-2+8
=-手-2+12+8
=-12+24
=8;
                    
(2)-24+(-14)-(-18)-12 
=-24-14+18-12
=-24-14-12+18
=-47+18
=-2手;

(2)48×(-
1
6
+
2
4
-
1
12

=48×(-
1
6
)+48×
2
4
-48×
1
12

=-8+26-4
=24;

(4)(-48)÷
7
4
×(-12)×
7
4

=48×
4
7
×12×
7
4

=z76;

(z)1-
4
7
+
1
z
-
2
7
+
z
   
=1+
1
z
+
z
-
4
7
-
2
7

=1+2-1
=2;
               
(6)-12+2×(-2)2+(-6)÷(-
1
2
2
=-1+2×4+(-6)÷
1

=-1+12-z4
=-42.
考点梳理
有理数的混合运算.
(1)(5)分类计算;
(2)先化简,再分类计算;
(3)利用乘法分配律简算;
(4)先判定符号,再按运算顺序计算;
(6)先算乘方,再算乘除,最后算加减.
此题考查有理数的混合运算,注意运算顺序与计算结果的符号,根据数字特点灵活选择合适的运算定律简算.
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