Repetition of a symbol in Roman numeral means

Explanation for the repeation of Roman symbol

Repetition of Roman numerals means addition

Taking example of $\text{XXX}$

We know that $\text{X}$ as Roman symbol represents $10$

So, $\text{XXX}$$=\text{X+X+X}$

$=10+10+10$

$=30$

Similarly $\text{XXXIII}$ represents $10+10+10+1+1+1$$=33$

Hence, repetition of a symbol in Roman numeral means addition.