=(3/10/99+4/11/119-5/8/299)*(3/6-2/6-1/6)
=(3/10/99+4/11/119-5/8/299)*(1/6-1/6)
=(3/10/99+4/11/119-5/8/299)*0
=0
=(3/10/99+4/11/119-5/8/299)*(3/6-2/6-1/6)
=(3/10/99+4/11/119-5/8/299)*(1/6-1/6)
=(3/10/99+4/11/119-5/8/299)*0
=0
1+2-3-4+5+6-7-8+9+10-11-12+...-299-300+301+302 = ?
A = 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+13+14-...-299-300+301+302 =?
A = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 - 11 - 12 + ......... - 299 - 330 + 301 + 302 = ?
Ti'nh Tong
D = 1 +2 - 3 -4 + 5 + 6 - 7- 8 + 9 +10 - 11 -12 + ....... - 299 - 300 +301 +302
Tinh nhanh
A = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 - 11 - 12 + ......... + 299 - 300 + 301 + 302
Tính nhanh :
1+2-3-4+5+6-7-8+9+10-11-12+13+14-...-299-300+301+302
Tính nhanh:
a) (1374.57+687.86).(26.14+74.14)
b)99-97+95-93+91-89+...+7-5+3-1
c)5+6-7-8+9+10-11-12+13+...-299-300+301+302
tính nhanh
a, 125,125 + 175,175 + 214,214 + 172,172 + 219,219
b,1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 - 11 - 12 + ... + 298 - 299 - 300 + 301