■■■■-■■■■≠????

■■■■-■■■■=0
so it ≠all number

2007-01-14 20:02:54 補充：
for example 1-1=0it would not equal to another number.■■■■ and ■■■■ is the same thing so it ≠any number except 0

■■■■-■■■■≠0

■■■■ ( ■■■■-■■■■of course not = ■■■■ )