Using four numbers, try and arrive at exactly two four by adding, subtracting, multiplying or dividing each number exactly once.
Includes a difficulty slider (using www.4nums.com data) to help practice harder puzzles. Also has color themes, dark mode, undo/redo, and multiply/divide all buttons. Altogether much more usable and complete than the other 24 apps out there!
This is a completely free and open source application without ads or tracking of any kind. See the full source here: https://github.com/misprit7/two-dozen