1+2+3+4+5+6+7+8+9=
(1+9)+(2+8)+(3+7)+(4+6)+5=
10+10+10+10+5=
40+5=
45
k mik nha bạn , làm ơn
\(1+2+3+4+5+6+7+8+9\)
\(=\left(1+9\right)+\left(2+8\right)+\left(3+7\right)+\left(4+6\right)+5\)
\(=10+10+10+10+5\)
\(=10.4+5\)
\(=40+5\)
\(=45\)
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9
= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5
= 10 + 10 + 10 + 10 + 5
= 45
tk mk nha
=[1+9]+[2+8]+[3+7]+[4+6]+5
=10 + 10 + 10 + 10 +5
=45
mik đi
1+2+3+4+5+6+7+8+9
= ( 1+9)+ ( 2+8)+ (3+7)+ (4+6)+ 5
= 10+10+10+10+5
=10*4+5
=40+5
=45
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9
= (1 + 9) + (2 + 8) + (3 + 7) + (4 + 6) + 5
= 10 + 10 + 10 + 10 + 5
= 10 x 4 + 5
= 40 + 5
= 45
k cho tớ nha Trương Thanh Nhân
1+2+3+4+5+6+7+8+9
= (1+9)+(2+8)+(3+7)+(4+6)+5
= 10 + 10 + 10 + 10+ 5
= 10 x 4 + 5
= 40 + 5
= 45
1+2+3+4+5+6+7+8+9
=(1+9)+(2+8)+(3+7)+(4+6)+5
=10 +10 +10 +10 +5
= 45
bạn ạ
1+2+3+4+5+6+7+8+9
=(1+9)+(2+8)+(3+7)+(4+6)+5
=10+10+10+10+5
=10x4+5
=45
K mk!, hok giỏi na! C ơn bn nếu bn k mk
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9
= ( 1 + 9 ) + ( 2 + 8 ) + ( 3 + 7 ) + ( 4 + 6 ) + 5
= 10 + 10 + 10 + 10 + 5
= 10 x 4 + 5
= 40 + 5
= 45
1+2+3+4+5+6+7+8+9
=(1+9)+(2+8)+(3+7)+(4+6)+5
=10+10+10+10+5=45