The numbers in the red boxes will give the passcode. Following is the solution to the given table:
Row 1: 6+1+15+5
Row 2: 3+11+9+14
Row 3: 10+16+13+14
Row 4: 8+12+2+7
You will need to enter the numbers from top to down. So press the keypad and input 91412 and press OK. You can now proceed to the next level.