C=1.2+2.3+3.4+4.5...+ 99.100
C=1.2.3+2.3.3+3.4.3+4.5.3+...+99.100.3
3C=1.2.3+2.3.(4-1)+3.4.(5-2)+4.5.(6-3)+...+99.100.(101-98)
3C=1.2.3+2.3.4-1.2.3+3.4.5-2.3.4+4.5.6-3.4.5+...+99.100.101-98.99.100
3C=99.100.101
C=33.100.101=333300
D = 2^2+4^2+6^2+...+98^2
1/4D=1^2+2^2+3^2...49^2
1/4D=((1+49^2)49:2=58849
D=58849.4=235396