Question

[Phạm Ngọc Hương]

a) S= 1/1*2 + 1/2*3 + 1/3*4 + ...............+ 1/99*100

Answer 1

[KARRY WANG]

S=1/1*2+1/2*3+1/3*4+......+1/99*100

S=1-1/2+1/2-1/3+1/3-1/4+......+1/99-1/00

S=1-1/100

S=99/1000

vậy S=99/100