Finding present values. Am I doing this right?

1. Use an annual interest rate of 10.5% to calculate the present value of an income stream of $1,000 received at the end of each year for the next ten years. (We're not using calculus with this.)

My solution is to use PV = 1000/(1+10.5%)^t, where t = the year in question.

2. Use an annual interest rate of 18% (compounded monthly) to calculate the present value of $100 received at the end of each month for the next 120 months.

My solution is to use PV = 100/(1+18%/12)^t, where t = the month in question.

Are these correct?

Question

Finding present values.  Am I doing this right?

1. Use an annual interest rate of 10.5% to calculate the present value of an income stream of $1,000 received at the end of each year for the next ten years.  (We're not using calculus with this.)

My solution is to use PV = 1000/(1+10.5%)^t, where t = the year in question.

2. Use an annual interest rate of 18% (compounded monthly) to calculate the present value of $100 received at the end of each month for the next 120 months.

My solution is to use PV = 100/(1+18%/12)^t, where t = the month in question.

Are these correct?