1+2+3+4+5+6+7+8+9+10+11+12+13+14=(1+14)+(2+13)+(3+12)+(4+11)+(5+10)+(6+9)+(7+8)
=15+15+15+15+15+15+15
=15*7=105
1+2+3+4+5+6+7+8+9+10+11+12+13+14=(1+14)+(2+13)+(3+12)+(4+11)+(5+10)+(6+9)+(7+8)
=15+15+15+15+15+15+15
=15*7=105
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18 + 20
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19
Tính nhanh :
1+2-3-4+5+6-7-8+9+10-11-12+13+14-...-299-300+301+302
Tính nhanh
1×2×3×4×5×6×7×8×9×10×11×12×13×14×15×16×17×18×19×20
tính nhanh
1+3+5+7+9+11+13+15
2+4+6+8+10+12+14+16
1+4+7+10+13+16+16+22
1+5+9+13+17+21+25+29+33+37
cứu mình với.HELP ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1+2-3-4+5+6-7-8+9+10-11-12+13+14-...-299-300+301+302 =?
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14=
1+[2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17]*0,000001
1+2-3-4+5+6-7-8+9+10-11-12+13+14-15-16+...+301+302
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20=?