Question

tính nhanh :1+2+3+4+5+6+7+8+9+10

 

Answer 1

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

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

= 10 + 10 + 10 + 10 + 5 + 10

= 10 x 5 + 5

= 50 + 5

= 55

Answer 2

55

mk tl dau tien

tick nha!!(^.^)

Answer 3

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

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

= 10 +10 +10 +10 +10 +5

= 55

Answer 4

 ta bỏ chúng trong ngoặc cho dễ tính

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

= 10 + 10 +10 + 10 + 10 + 5

=50 + 5 

= 55

Answer 5

ghncvnbcvhvnvchn