Back in the days of Roman numerals, basic multiplication was considered this incredibly technical concept that only official mathematicians could handle, but then once Arabic numerals came around, you could actually do arithmetic on paper, and we found that 7-year-olds can understand multiplication.
It's not that multiplication itself was difficult. It was just that the representation of numbers — the interface — was wrong
— Bret Victor - in interview: The Utopian UI Architect
it's a question meant to stimulate thought: what design process could take you from Roman numerals to Hindu-Arabic numerals? (...) it seems fair to say that any person who could invent Hindu-Arabic numerals, starting from the Roman numerals, would be both one of the great mathematical geniuses who ever lived, and one of the great design geniuses who ever lived. They'd have to be extraordinarily capable in both domains, capable of an insight-through-making loop which used the evolving system of numerals to improve not just their own mathematical ideas, but to have original, world-class insights into mathematics; and also to use those mathematical insights to improve their evolving system of numerals
— Andy Matuschak, Michale Nielsen - How can we develop transformative tools for thought?