What it does
01
Set your own pace
Pick the digits, the count and the display speed, then start. Numbers appear one at a time; when they are done, enter a single total to be scored.
02
Instant scoring
Right or wrong is shown with a mark and a sound, and you can review your results for the session. Interrupted rounds do not count.
03
Light by design
No network and no account. Works on iPhone and iPad, following your device's Japanese or English setting.
Made for iPhone Duo
Set it half open like a laptop: the numbers flash on the upper screen, and the lower screen shows your progress, then becomes the number pad.
Half open
The flash above; which problem you are on and your progress below. When it is time to answer, the lower screen turns into the number pad, so your eyes stay on the flash and your thumbs on the keys.
Fully open
The regular layout fills the large inner display. Held like a book, the flash goes left and progress and the number pad go right.
Closed
The outer display runs the regular iPhone layout.
Price
Free.