If i enter 7,8, or 9 in a cell, i want the cell below to be a 10. Likewise if i enter a 10, i want the cell below to default to 9.

How would i go about doing that?

Yes, it's a boxing scoring spreadsheet

 

use the =IF() function.

 

I couldn't get it to work and couldn't find relevant examples.

 

basic example, assuming the first score is in cell a1 for simplicity

in cell b1 you would enter something like =if(a1=10,value if true, value if false)

so it would look like =if(A1=10,9,10)

For your requirements something like =if(A1<10,10,9) which has more scope than the first example should cover your needs

Copy the formula down from cell b1