Excel 2010, how to use formulas from other, dedicated worksheet ?

As an example, the SUM in cell E10 of worksheet “A” could lead to two different formulas :

1. =IF(E10<100, . . . . “use formula “x”, or
2. =IF(E10>101, . . . . “use formula “Y”

In which case the result would reflect in cell E11 of worksheet “A”.

Question: Is there a way to use one dedicated, collective worksheet, ea. worksheet “B”, for these and other formulas that I could refer to like in above formula 1. and 2. If “yes”, how ?

Thank you for your advice.