Roman numerals - Wikipedia

Roman numerals - Wikipedia

Arabic numerals - Wikipedia

Roman numerals - Wikipedia

Roman numerals - Wikipedia

upload.wikimedia.org/wikipedia/en/thumb/1/1e/Sums_

Roman numerals - Wikipedia

File:Roman numeral 1000 C D.svg - Wikipedia

Fibonacci sequence - Wikipedia

Roman numerals, Numerals Wiki

What is the number forty in Roman numerals? - Quora