You can use the SUMIF function in Excel to add up combinations of numbers from a list that match a specified total. Here's how:

1. First, make sure your list of numbers is in a column in Excel.
2. Next, decide on the total you want to match. Let's say you want to find all combinations of numbers that add up to 10.
3. In a new cell, enter the formula "=SUMIF(A:A,"="&10,B:B)", where A:A is the column with your list of numbers and B:B is the column where you want to display the results.
4. Press enter and Excel will display the sum of all combinations of numbers from your list that add up to 10.

Note that this formula will only work for combinations of two numbers. If you want to find combinations of three or more numbers, you'll need to use a more complex formula. One option is to use the SUMIFS function, which allows you to specify multiple criteria. For example, "=SUMIFS(B:B,A:A,"<"&10,B:B,"<"&10)" will find all combinations of three or more numbers that add up to less than 10.