Square of 2-cubic of 2-quartic of 2-quintic of 2-/quadratic of kloc-0/9+quadratic of 20.

=2+2^2

=6

Because 2 20 = 2 * 219.

2^ 19=2*2^ 18

……

1×3| 2+3×5| 2+5×7| 2+9× 1 1| 2+ 1 1× 13.

=2/( 1*3)+2/(3*5)……+2/( 1 1* 13)

Because d/[n * (n+d)] =1/n-1/(n+d) (/stands for fraction).

= 1- 1/3+ 1/3……+ 1/ 1 1- 1/ 13

= 1- 1/ 13

= 12/ 13