If I’m understanding correctly, you want to make sure you’ve entered the miles for each state correctly and verify they add up to what you’ve entered for start/stop odometer readings? If that’s correct, you could set up conditional formatting for your Total Miles column to change the fill color to red or something obvious. It would be a formula that checks if Column G + Column H does not equal Column L. If the formula proves to be true, it would highlight the cell in Column L to alert you something isn’t correctly entered. That’s the concept, if you want help implementing, I will go through the process in more detail when I’m near my computer.