find the $2021$ term

double digit $=90\times 2$

we need ${2021}^{\mathrm{st}}$ digit

Till two digit number we have $189$ digit

we need $2021-189=1832$ digit

triple digit $=\frac{1832}{3}=610\times 3+2$

we take $610$ three digit number

$100,101,\dots \dots ..,709$

Ans $=1$