15  REM
20  DIM I$[45]
30  DATA "TYPE THE NUMBER OF OPTION DESIRED"
40  DATA "THEN INPUT APPROPRIATE VALUES"
50  DATA "TO QUIT HIT THE BREAK KEY."
60  DATA "ABACUS 0PTIONS:"
70  DATA "1)A+B=C"
80  DATA "2)A-B=C"
90  DATA "3)A*B=C"
100  DATA "4)A/B=C"
110  DATA "5)A^B=C; 'A' TO THE 'B' POWER EQUALS 'C'"
120  DATA "6)A^(1/B)=C; 'A' TO THE 'B' ROOT EQUALS 'C'"
125  DATA "7)SQR(A)=C"
130  DATA "8)100*(A/B)=C%"
140  DATA "9)A/B=C/D; SOLVE FOR 'C'"
150  DATA "10)A/B=C/D; SOLVE FOR 'D'"
180  READ I$
190  PRINT I$
200  IF TYP(0) <> 3 THEN 180
210  PRINT 
212  PRINT "YOUR CHOICE";
220  INPUT S
230  RESTORE 
240  FOR I=-3 TO S
250  READ I$
260  NEXT I
270  PRINT 
280  PRINT I$
290  PRINT "A=";
300  INPUT A
305  IF S=7 THEN 330
310  PRINT "B=";
320  INPUT B
330  GOSUB S OF 350,370,390,410,430,450,465,470,510,540
340  GOTO 210
350  PRINT "C="A+B
360  RETURN 
370  PRINT "C="A-B
380  RETURN 
390  PRINT "C="A*B
400  RETURN 
410  PRINT "C="A/B
420  RETURN 
430  PRINT "C="A^B
440  RETURN 
450  PRINT "C="A^(1/B)
460  RETURN 
465  PRINT "C="INT(SQR(A)*1000+.5)/1000
467  RETURN 
470  PRINT "C%="A/B*100
480  RETURN 
510  PRINT "D=";
515  INPUT D
520  PRINT "C="(A/B)*D
530  RETURN 
540  PRINT "C=";
550  INPUT C
560  PRINT "D="B/A*C
570  RETURN 
580  END 
