Adding Minutes:Seconds

When I format cells to number>time>and choose 13:01 the cell defaults to clock time rather than Min:Sec. For instance, typing in 6:47 displays 6:47:00 AM. What format can I be in so I can a column of min:sec and get a sum of hr:min:sec. I must be missing something.

It doesn't matter how the cell is formatted, if you want 6:47 interpreted as 6 minutes 47 seconds then input as 0:06:47.

You can format as m:ss to display as just 6:47

You can then just use SUM to sum the column, format SUM cell as [h]:mm:ss