one digit arithmetic

This App "one digit +-x÷" is one digit arithmetic training App. And this is a searching game, too.This App has four categories, addition:"one digit +" subtraction:"one digit -" multiplication:"one digit x" and division:"one digit ÷". Each category has 9 questions on nine stages, random 81 questions."one digit +" : from "1 + 1 = 2" to "9 + 9 = 18"."one digit -" : from "2 - 1 = 1" to "18 - 9 = 9"."one digit x" : from "1 x 1 = 1" to "9 x 9 = 81"."one digit ÷" : from "1 ÷ 1 = 1" to "81 ÷ 9 = 9".*** LITE VERSION (FREE)***one digit +9x9 Speed**********