How to keep one variable constant with other one changing with row in excel

Question

Lets say I have one cell A1, which I want to keep constant in a calculation. For example, I want to calculate a value like this:

=(B1+4)/(A1)

Answer 1

For future visitors - use this for range: ($A$1:$A$10)

Example
=COUNTIF($G$6:$G$9;J6)>0