SEAMO 2027 - Paper C - SET 04 - Self-study Question 8

Evaluate $N/D$, where $$N=(2^2+4^2+\cdots+100^2)-(1^2+3^2+\cdots+99^2),$$ $$D=1+2+3+\cdots+9+10+9+\cdots+3+2+1.$$