Problem with Type conversion- String to Int

Hiii all,
I have a requiremnt where I need to convert an expression in string into Integer. I used CInt function but its givin error. Pleaseeee help .Not able to solve the issue


I have to extract each DIGIT ( for further calculations) after combining the values in 4 different columns.Used the MID function fr that and the MID function can accept only strings.
( Here have shown extraction of only 3 digits to avoid complication)

How to cnvert string to integer in this code without any error or Type MisMatch? Pleaaase help.

Sub Check()
Dim conced_num As String
Dim res
Dim cd As Integer

For i = 4 To 8

conced_num = Cells(i, 3).Value & Cells(i, 5).Value & Cells(i, 15).Value & Cells(i, 22).Value

res = CInt( (Mid(conced_num, 3, 1)) ) * 89 + CInt( (Mid(conced_num,2,1)) ) * 17 + CInt( (Mid(conced_num,1,1)) ) * 16 

cd = 98 - (res Mod 93)

 Next i
 
End Sub

Nope it is highlighin the followin part in yellow color.

res = CInt((Mid(conced_num, 3, 1))) * 89 + CInt((Mid(conced_num, 2, 1))) * 17

You need to look in the values of

Mid(conced_num, 3, 1)

and

Mid(conced_num, 2, 1)

they probably contain text or characters that cannot be converted to integers