Help on Microsoft Excel (on Mac) please!

Hello,
Does anyone know if there are key shortcuts for the following functions?

1). changing a cell reference in a formula to $..$ (e.g. $A$1) format. When I copy a formula containing this cell, this cell will be treated as "absolute" i.e. its value won't be changed following the change of column or row etc. In windows, I can type A1 and then press F4 to turn "A1" to "$A$1"

2). recalculate the whole sheet. In windows, I can press F9

The problem with these key shortcuts is that they've been used by Mac already and I can't find a way to reset them.

Thanks a lot!