How to play

1. Add a profile with your name and level. Everyone on this device can have their own.
2. Pick a topic card. Read the key idea, then tap through the worked example.
3. Practise. Each answer shows its working, and hints are there when you're stuck.
4. Open the Progress page to see which kinds of slip come up most often.

Level guides

Read the key ideas for a level before or after you play.

• Level 1
• Level 2
• Level 3
• Level 4
• Level 5
• Level 6
• Level 7
• Level 8
• Level 9
• Level 10
• Level 11
• Level 12