Ta chia thành: 1 + (2-3-4+5) + (6-7-8+9)+....+(298-299-300+301) + 302 = 1 + 0 + 0 + 0 + .....+ 0 + 302 = 1+302 = 303
**** cho mk nha bạn !!!
1+2-3-4+5+6-7-8+9+10-11-12+...-299-300+301+302
1+2-3-4+5+6-7-8+9+10-11-12+...-299-300+301+302
1+2-3-4+5+6-7-8+9+10-11-12+..........-299-300+301+302
1+2-3-4+5+6-7-8+9+10-11-12+....-299-300+301-302
B=1+2-3-4+5+6-7-8+9+10-11-12+.........-299-300+301+302 = ?
B= 1+2-3-4+5+6-7-8+9+10-11-12+...-299-300+301+302
1+2-3-4+5+6-7-8+9+10-11-12+........+298-299-300+301+302 = ?
tính:
1+2-3-4+5+6-7-8+9+10-11-12+...-299-300+301+302.
Tinh nhanh: M=1+2-3-4+5+6-7-8+9+10-11-12+...+...298-299-300+301+302