0%
overall
Single digits
0 – 9 · 10 prompts per session
Level 2 Teens
10 – 19
Level 3 Round tens
20, 30 … 100
Level 4 The twenties
21 – 29
Level 5 Compound 30 – 99
31, 42, 55 …
Level 6 Hundreds
100, 200 … 900
Level 7 Mixed 0 – 999
Everything so far
Level 8 Thousands
1,000 – 50,000
Level 9 Compound thousands
1,001 – 10,101
Level 10 Millions & billions
100,000 – 1,000,000,000