(1)3×
+2 3
,1 18
=2+
,1 18
=2
,1 18
答:2
比3个1 18
的积多2 3
;1 18
(2)5.6÷(3.6-1.6×0.5),
=5.6÷(3.6-0.8),
=5.6÷2.8,
=2,
答:商是2;
(3)设A与B的平均数x,
2x+(x+2)×2=25×4,
2x+2x+4=100,
4x+4-4=100-4,
4x=96,
4x÷4=96÷4,
x=24,
24×2-28,
=48-28,
=20,
答:B是20.