10 CLS
20 PRINT "PRINCIPAL ON A LOAN" 
30 DEFDBL A-Z
40 PRINT 
50 PRINT "REGULAR PAYMENT"; 
60 INPUT R 
70 PRINT "TERM IN YEARS"; 
80 INPUT Y 
90 PRINT "ANNUAL INTEREST RATE"; 
100 INPUT I 
110 PRINT "NUMBER OF PAYMENTS PER YEAR"; 
120 INPUT N
130 P=R*N*(1-1/((I/100)/N+1)^(N*Y))/(I/100) 
140 PRINT "PRINCIPAL = $";INT(P*100+.5)/100 
150 PRINT 
160 PRINT "MORE DATA? (1=YES, 0=NO)"; 
170 INPUT X 
180 IF X=1 THEN 40   
190 END