The stick figure is having a mathematical breakdown with Roman numerals! Looking at I + I = II (1+1=2), then II + II = IV (2+2=4)... wait, no, that's wrong! It's "I5" instead of IV! And then I5 + 5 = II0?! The caption brilliantly trolls us with terrible advice to "replace Roman numerals with modern ones when doing math" — which is exactly what caused this numerical train wreck. The poor stick figure is using the symbol "I" as the digit "1" and treating Roman numerals like positional notation. This is what happens when civilizations collide and your number systems get confused. Caesar would be rolling in his grave... or should I say, he'd be rolling MCMLXXXIV times.