Let's convert each fraction to a decimal:

1. $\frac{4}{20} = 0.2$
2. $\frac{2}{20} = 0.1$
3. $\frac{4}{10} = 0.4$
4. $\frac{17}{20} = 0.85$
5. $\frac{15}{20} = 0.75$
6. $\frac{4}{5} = 0.8$
7. $\frac{10}{20} = 0.5$
8. $\frac{5}{20} = 0.25$
9. $\frac{1}{2} = 0.5$
10. $\frac{16}{20} = 0.8$
11. $\frac{19}{20} = 0.95$
12. $\frac{13}{20} = 0.65$

Let me know if you want further details or have any questions about these conversions.

Here are five related questions to deepen your understanding:

1. How do you simplify fractions before converting them to decimals?
2. Why is $\frac{1}{2}$ the same as 0.5?
3. How do you convert fractions to percentages after finding the decimal form?
4. What is the relationship between fractions, decimals, and percentages?
5. Can you convert any fraction to a decimal without a calculator?

Tip: When converting a fraction to a decimal, divide the numerator by the denominator.