## Explanation

Both formulas use built-in functions to calculate a subtotal, but the syntax used by SUMIF and SUMIFS is slightly different:

```
SUMIF(range,criteria,sum_range)
SUMIFS(sum_range,range,criteria)
```

In both cases, note that the region "West" must be enclosed in double quotes, since it is a text value.

Whether you use SUMIF or SUMIFS (which can handle more than one criteria) is a matter of personal preference. SUMIFS was introduced with Excel 2007, so it's been around now for a long time.