其它
If $A=1+3+5+7+\cdots +99$, and $B=2+4+6+\cdots +100$, what is the value of $B-A$? 
Overseas Competition->Knowledge Point->Calculation Modules->Sequences and Number Tables->Arithmetic Sequences
$B-A=(2-1)+(4-3)+(6-5)+\cdots +(100-99)=50$ 