QBASIC Code for a simple calculator program

Calc.bas

CLS
SCREEN 13
PRINT "CALCULATOR-"
PRINT "ENTER YOUR EXPRESSION"
PRINT "EXAMPLE-58 * 20"
PRINT "THE TERMS SHOULD BE SEPARATED BY SPACE OR ERROR WILL OCCUR"

INPUT "ENTER YOUR EXPRESSION-"; EXP$

EXP$ = EXP$ + " "
INDEX = 1
DIM TERMS(3) AS INTEGER

FOR I = 1 TO LEN(EXP$)
    CURRENTTOKEN$ = MID$(EXP$, I, 1)
    IF CURRENTTOKEN$ = " " THEN
        IF INDEX = 2 AND OPERATION$ = "" THEN
            OPERATION$ = TERMCURRENT$
        ELSE
            TERMS(INDEX) = VAL(TERMCURRENT$)
            INDEX = INDEX + 1
        END IF
        TERMCURRENT$ = ""
    ELSE
        TERMCURRENT$ = TERMCURRENT$ + CURRENTTOKEN$
    END IF
NEXT I



SELECT CASE OPERATION$
    CASE "+"
        R = TERMS(1) + TERMS(2)
    CASE "*"
        R = TERMS(1) * TERMS(2)
    CASE "-"
        R = TERMS(1) - TERMS(2)
    CASE "/"
        R = TERMS(1) / TERMS(2)
    CASE "%"
        R = TERMS(1) MOD TERMS(2)
    CASE "^"
        R = TERMS(1) ^ TERMS(2)
END SELECT
PRINT TERMS(1); OPERATION$; TERMS(2); "="; R

31 SELECT CASE OPERATION$
this is trowing error, illegal between select case and case
what is the problem
i am a beginner

how do i fix the error in line 31
illegal between select case and case

how do i fix the error in line 31 illegal between select case and case

did u put a space between two characters?

WRONG : 2+2
RIGHT : 2 + 2

CLS

INPUT "ENTER ANY NUMBER"; N

A N

S = 0

WHILE N <> 0

RN MOD 10

S S 10+ R

N = N \ 10

WEND

IF A = S THEN

PRINT A; "IS PALINDROME"

ELSE

PRINT A; "IS NOT PALINDROME"

END IF

END