Based on the profound principle: Slow and steady wins the race
1) Start with manageable steps.
2) Having mastered that step, take a small step forward.
3) Keep moving forward without taking a break... and success is sure to follow.
This app starts out with extremely simple and manageable steps
Day 1: Add by 1
2) Having mastered adding by one, you move to day 2.
Adding 1+2 to 5+2 (not 1+2 to 10+2). Remember, simple manageable steps.
3) Day 3: 6+2 to 10+2
... you get the drill.
Same goes for Subtraction.
Practice 30 questions a day. You can set the pace for you child using the settings menu. However you can answer no more than 3 questions wrong within the time allotted to move to next day.
On completing a day successfully, you get a checkmark against that day. This helps keep track of progress and provides motivation.
An extremely simple principle indeed!
Yet more effective than any other approach you can take to acquire a new skill.