Given Roman numeral is meaningful or meaningless: $LXXIV$

Give the answer for the following in the roman numerals

$\mathrm{XC}+\mathrm{X}$.

Give the answer for the following in the roman numerals

$\mathrm{XXX}-\mathrm{V}$.

Give the answer for the following in the roman numerals

$\mathrm{XCII}-\mathrm{XXVII}$.

Give the answer for the following in the roman numerals

$\mathrm{XLIV}+\mathrm{XX}$.

Give the answer for the following in the roman numerals

$\mathrm{XCV}-\mathrm{LXXV}$.