Fun to learn first numbers with kids! Count, listen, read. Three the most popular languages in the world (by native speakers). Arabic and Roman numerals. Arranged in Latin square, by the way (as a little Sudoku). Periodic testing is also big fun: turns "thinking emoji" into "happy emoji". Designed for iPhone and iPad. Works perfectly in any device orientation - portrait, landscape, or even upside down - numbers and words are always upright. Speaker sound ON/OFF is controlled by Ring/Silent switch on iPhone (headset is always ON, please adjust the volume). Background melodic ostinato momentarily can be turned ON/OFF via the settings button ("gear" icon).