Greatest integer function
f(x)=[x]={\begin{matrix}0 ;0\leq x<1 \\ -1 ;-1\leq x <0 \\ -2 ;-2\leq x<-1\end{matrix}
Given series
S=[−31]+[−31−1001]+[−31−1002]+[−31−1003]+…+[−31−10099]
General term {T}_{r}=[-\frac{1}{3}-\frac{r}{100}]={\begin{matrix}-1 0\leq r\leq 66 \\ -2 r>66\end{matrix}
⇒S=r=0∑66(−1)+r=67∑99(−2)=(−67)+(−2)×33
=−133