Question

tính tổng dãy số sauB=1+2-3-4+5+6-7-8+9+10-11-12+...-299-300+301+302

Answer 1

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)+.......+(298-299-300+301)+302

B = 1+0+0+....+0+302

B = 1+302

B = 303