Question

[Trịnh Thị Thùy Dương]

1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9+10+10=

Answer 1

[꧁༺Áς❤๓ค❤đếภ❤từ❤tђเêภ❤đườภﻮ༻꧂]

1 + 1 + 2 + 2 + 3 + 3 + 4 + 4 + 5 + 5 + 6 + 6 + 7 + 7 + 8 + 8 + 9 + 9 +10 +10  

= (1+9) + (1+9) + (2+8) + (2+8) + (3+7) + (3+7) + (4+6) + (4+6) + (5+5) + 10+10

= 10 + 10 +10 + 10 +10 +10 +10 +10 + 10 + 10 +10

= 10 x 11

= 110

Answer 2

[Lương Bửu An]

110