Maths Training started its life as a third-party game, part of the Kageyama Method series published in Japan by Shogakukan. It's a localized version of either 2006's Kageyama Method: Masu x Masu Hyaku-masu Keisan (Kageyama Method: Repeat x Repeat 100-cell Calculation Method, basically) or its sequel. Sadly, this probably isn't the Masu x Masu game advertised so breakdancically last month, because that one also contains kanji training.
Even though we are just now hearing about this, Nintendo is planning a February 8th release in Europe. We've included the press release after the break. Try out the 1-button Clicking Method to give it a look.