Number and Counting System

Teach me the number system in [TARGET LANGUAGE].

Please cover:
1. Cardinal numbers:
   - 0-20 (with pronunciation)
   - 21-100
   - Hundreds, thousands, millions
   - Number formation patterns/rules

2. Ordinal numbers (first, second, etc.)
3. Fractions and decimals
4. Percentages
5. Math operations (add, subtract, etc.)
6. Special counting systems (if applicable):
   - Counters/classifiers
   - Different number sets for different objects

7. Practical applications:
   - Telling time
   - Dates
   - Phone numbers
   - Addresses
   - Money and prices
   - Measurements
   - Ages

8. Number-related vocabulary (half, double, approximately)
9. Cultural significance of numbers (lucky/unlucky)
10. Common mistakes with numbers
11. Practice exercises:
    - Listening and writing numbers
    - Saying prices
    - Dates and times
12. Quick reference chart