To convert the expression $2 \times 10^4 + 0 \times 10^3 + 3 \times 10^2 + 5 \times 10^1 + 7 \times 10^0$ into decimal notation, we calculate each term individually:

1. $2 \times 10^4 = 20000$
2. $0 \times 10^3 = 0$
3. $3 \times 10^2 = 300$
4. $5 \times 10^1 = 50$
5. $7 \times 10^0 = 7$

Now, we add these values together:

$20000 + 0 + 300 + 50 + 7 = 20357$

Thus, the number in decimal notation is 20357.

Do you want further details or have any questions? Here are some related questions you might consider:

1. How would you express this number in scientific notation?
2. What is the significance of each digit in a number?
3. Can you explain how to convert other numbers from expanded form to decimal?
4. What is the difference between decimal notation and scientific notation?
5. How can we apply similar calculations in real-world scenarios?

Tip: Always break down each term when converting from expanded form to ensure accuracy.