I have a single column list of rows that I pasted into Excel that looks like:

```
1:15
0:25
0:43
```

These represent hours and minutes worked each day. I want to sum up the total and see how many hours I have worked. I can't seem to figure out how to do this in Excel. I know I use the formula:

`=FIRSTCOLUMN+LASTCOLUMN`

The issue is that the column does not seem to be formatted correctly.