After returning to this game to find that the Japanese calculator is 404'd, I've been looking for a replacement calculator, and I found a link to only one calculator by googling "Rydia's Mathemagic Minute":
It wasn't a very good one solely based on the fact that it wouldn't always use all the numbers, and it only ever gave you one solution. However, it did let me know what kind of game Rydia's Mathemagic Minute is.
Rydia's Mathemagic Minute is essentially a game of Countdown, but unlike the British game show, it has two additional rules (You must use all the numbers, the goal is always 10).
Here's a link to the better countdown solver, which gives multiple solutions, including ones that use all four number:
If this link ever goes 404 as well, now everyone should know just to lookup "Countdown Calculator" for a replacement calculator.