Press and select 1. 

Displays the TVM Solver. 

To calculate the payment, scroll down to PMT and press . Borrowing $25000 for 60 months at 5.25% will result in a payment of $474.65. 
Press ; 1; 2. The values are entered as: tvm_Pmt(N,I%,PV,FV,P/Y,C/Y). All values are not necessary. Those with a value of 0 can be omitted. 
Press ; 1; 3. The values are entered as: tvm_I%(N,PV,PMT,FV,P/Y,C/Y). Notice that PMT is entered as a negative value. Paying $450 per month for 60 months on a loan of $2500, means that the interest rate is 3.07%. 
Press ; 1; 4. The values are entered as: tvm_I%(N,I%,PMT,FV,P/Y,C/Y). Paying $450/month for 60 months, will pay off a loan of $23692.46 at an interest rate of 5.25%. 
Press ; 1; 4. 