101+100+99+98+...+3+2+1/101-100+99-98+...+3-2+1
B=(101+100+99+98+.....+3+2+1) / (101-100+99-98+.......+3-2+1)
B=(101+100+99+98+.....+3+2+1) / (101-100+99-98+.......+3-2+1)
A=101+100+99+98+...+3+2+1/101-100+99-98+...+3-2+1
101 +100+99+98+.........+3+2+1
101-100+99+98+.....+3-2+1
101+100+99+98+...+3+2+1
101-100+99-98+...+3-2+1
Rút gọn S=101+100+99+98+...+3+2+1 :101-100+99-98+...+3-2+1
101 + 100 + 99 + 98 + .... + 3 + 2 + 1
_______________________________
101 - 100 + 99 - 98 + ... + 3 - 2 + 1
A] 101-100+99-98+.......+3-2+1
B] 101+100+99+98+.......+3+2+1