When you hold shift and press any keys from `,1,2,3,4,5,6,7,8,9,0,-, and = keys and a different symbol pops up you will need to troubleshoot the keyboard. 

Here is an example of this type of issue. When trying to access Shift-2 or the @ symbol instead the keyboard shows a parenthesis.

The steps below are here to assist you so this issue can be solved. 

1. Go to the Apple Main Menu
2. Click on "System Preferences"
3. Click on "Keyboard"
4. Choose "Input Sources"
5. Click on the "+" icon
6. Select layout language eg. English, US
7. Click "Add"
8. Select the layout you just created and close the window.