2013/2014*[21/47+19/251 / 11/13]*[1/1+5/7*7/15]
Tính bằng cách nhanh nhất:
a/ 2010-2012+2014-2016+2018-2020+2021-2022
b/ 1-3+5-7+9-11+13-15+17-19+21
1 × 2 + 2 × 3 +3 × 4 + 4 × 5 + 5 × 6 + 6 × 7 + 7 × 8 + 8 × 9 + 9 × 10 + 10 × 11 +11 ×12 + 12 ×13 + 13×14 + 14×15 + 15×16 + 16×17 +17×18 + 18×19 + 19×20 + 20×21 + 21×22 + 22×23 + 23×24 + 24×25 + 25×26
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30=
tính 1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50-999-888-777-666-555-444-333-222-111
nhanh nhé
38/25+9/10-11/15+13/21-15/28+17/36-19/45+21/55=
Điền vào dấu ? và cho biết quy luật nghen
a) 4-9-19-21-7-15-?
b) 11-13-17-25-32-37-?
c) 53-8-16-21-12-15-?
tinh
1+3+5+7+9+11+13+15+17+19+...+999+1000 = ?