以下是每一种方法的示例:
1. 20 - 1 = 19 2. 20 - 2 = 18 3. 20 - 3 = 17 4. 20 - 4 = 16 5. 20 - 5 = 15 6. 20 - 6 = 14 7. 20 - 7 = 13 8. 20 - 8 = 12 9. 20 - 9 = 11 10. 20 - 10 = 10
1. 20 - 1 = 19 2. 20 - 2 = 18 3. 20 - 3 = 17 4. 20 - 4 = 16 5. 20 - 5 = 15 6. 20 - 6 = 14 7. 20 - 7 = 13 8. 20 - 8 = 12 9. 20 - 9 = 11 10. 20 - 10 = 10