Give the answer for the following in Roman numerals.

$\mathrm{LXXIX}+\mathrm{XXI}$

Give the answer for $\mathrm{XLV}+\mathrm{LXI}$ in Roman numerals. $\left(\mathrm{CVI} / \mathrm{LCV} / \mathrm{XCV}\right)$

Select the correct answer.

Which of following is correct$?$

Select the correct answer.

Which digit cannot be written in Roman numerals$?$

The estimated addition of $345$ and $234$ up to the nearest $10$ is equal to:

The number of the expanded form $7\times 100000+5\times 10000+4\times 1000+2\times 10+9\times 1$ is :

The smallest counting number is _____.

The value of $\mathrm{CXIV}$ is _____.