120000 is financed for 30years at 5% APR. Calculate the monthly mortgage payment.

1. Convert the annual interest rate to a monthly rate:
r = \frac{0.05}{12}

2. Calculate the total number of monthly payments:
n = 30 \times 12 = 360

3. Substitute the values into the mortgage payment formula:
M = 120000 \frac{\left(\frac{0.05}{12}\right) \left(1 + \frac{0.05}{12}\right)^{360}}{\left(1 + \frac{0.05}{12}\right)^{360} - 1}

4. Calculate the final result:
M \approx 644.19

The monthly mortgage payment is approximately 644.19.