Feels like trial and error for me. Also the numbers aren't very clear, we have mistaken 100 for 200. And it really hard to notice that the egg has 0. But we did enjoy the humor:) and we do like the art style.
The font we found online looks like shit when resized, we wanted it to be a little bit of trial and error but it ended up leaving the player in the dark a little bit lol. Thanks for playing!