So I've got a spreadsheet with around 5 different rows, each one with a specific value (specifically a range of cells E2 - E8) and a "Total: " cell at the bottom, whose formula is this:

```
=Sum(E2:E8)
```

But when I enter the values, the Total: cell displays "###" as a result and anything that relies on the "total: " value does the same. I can't seem to figure out why. Could anyone shed some light on the problem? As far as I can tell there's nothing wrong with the formula, and the formatting of the numbers doesn't look wrong to me either.