Created with VanillaJS, HTML & CSS. It is for The Odin Project Assignment.
It does not handle 0.1 + 0.2 case, because why it should?
For more info, you can check IEEE 754
It may contain some bugs but I do not have time for insect powder.
It is responsive (by nature of flexboxes) but not mobile-friendly. So use desktop layout for best result.