练习题十
1.(1)2☆3=5,3☆2=10,所以不等.
-
a=b
-
无交换律2.6
3. 271
80
4.(1)3,0,2
(2)3,9,13
(3)12,26,33,45
5.提示:a&b = ab
a + b
= 1
1 + 1
a&b&c=
a b
1 = 1 ,
1 + 1 1 1 1
1
1 + 1 a b
c a + b + c
可以想象,3&4&5&6&20
1
= 1 1 1 1 1
+ + + +
3 4 5 6 20
= 1
20 + 15 + 12 + 10 + 3
60
= 1