Find the reciprocal sum of 1 * 2,2 * 3,3 * 4.99 * 100

Find the reciprocal sum of 1 * 2,2 * 3,3 * 4.99 * 100

1/1*2+1/2*3+1/3*4+.+1/99*100
=1-1/2+1/2-1/3+1/4-1/5+...+1/99-1/100
=1-1/100
=99/100