计算:(1)(24-12)-(18+6)(2)22-3-12+(3+1)-1(3)bab+b-aa-ab+a+ba-b(4)若a是2的小数部分,b是a的倒数,求ab+ba-4的值.-数学

24-

6

=

6
-
3

2
4


(2)原式=
2(2+

3
)
4-3
-2

3
+
1

3
+1

=4+2

3
-2

3
+

3
-1
2

=4+

3
2
-
1
2

=3
1
2
+

3
2


(3)原式=
b(

ab
-b)
ab-b2
-
a(a+

ab
)
a2-ab
+
a+b
a-b

=

ab
-b
a-b
-
a+

ab
a-b
+
a+b
a-b

=0;

(4)∵a是