5 + 4 + 3 + 2 + 1 + 5 + 6 + 7 + 8 + 9
= (5 + 5) + (4 + 6) + (3 + 7) + (2 + 8) + (1 + 9)
= 10 + 10 + 10 + 10 + 10
= 10 x 5 = 50
5+4+3+2+1+5+6+7+8+9
= ( 5 + 5 ) + ( 4 + 6 ) + ( 3 + 7 ) + ( 2 + 8 ) + ( 1 + 9 )
= 10 + 10 + 10 + 10 + 10
= 10 x 5
= 50
= (5+5) + (4+6)+(3+7)+(2+8)+(9 +1)
=10 + 10 + 10 + 10 + 10
=50
\(5+4+3+2+1+5+6+7+8+9\)
\(=\left(5+5\right)+\left(4+6\right)+\left(3+7\right)+\left(2+8\right)+\left(1+9\right)\)
\(=10+10+10+10+10\)
\(=10\times5=50\)