Formula for Selecting Values from a List

I'm not sure how to search for this as I don't know the "proper" terminology to use but I'm needing to write a formula that will provide the following results:

List of Values (in cells)
43
23
32
33
45
12
98
29

Select the 4 lowest values from the above list and total; ie. 12+23+29+32=86.

What type of formula would I use and what is this process called?

Thanks for your help.
Rob