1+2+3+4+5+6+7+8+9+10
= (1+10)+(2+9)+(3+8)+(4+7)+(5+6)
=11+11+11+11+11
=11x5
=55
=
1+2+3+4+5+6+7+8+9+10
=(1+9)+(2+8)+(3+7)+(4+6)+(5+10)
=10+10+10+10+15
=40+15
=55
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= (9+1) + (8+2) + (7+3) + (6+4) + 10 + 5
= 10 + 10 + 10 + 10 + 10 + 5
= 55
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5
= 10 + 10 + 10 + 10 + 5
= 45
\(1+2+3+4+5+6+7+8+9+10.\)
\(=\left(1+10\right)+\left(2+9\right)+\left(3+8\right)+\left(4+7\right)+\left(5+6\right)\)
\(=11+11+11+11+11\)
\(=11\times5\)
\(=55\)
(1+9) + (2+8) + (3+7) +(4+6)+ 5+ 10
= 10 + 10 + 10 + 10 + 10 + 5
=10 * 5 + 5
= 55
Chú ý : Dấu * là dấu nhân nhé .
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= ( 1 + 10 ) + ( 2 + 9 ) + ( 3 + 8 ) + ( 4 + 7 ) + ( 5 + 6 )
= 11 + 11 + 11 + 11 + 11
= 11 x 5
= 55
~ Chúc bạn học giỏi ! ~
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10
= ( 9 + 1 ) + ( 8 + 2 ) + ( 7 + 3 ) + ( 6 + 4 ) + 10 + 5
= 10 + 10 + 10 + 10 + 10 + 5
= 55