check if number in once cell exists in a range of cells and if yes, format another cell

I want to check if the number in one cell (eg.A1) has also been entered in one of a range of cells(eg.B1:F5) and if yes, I will conditionally format the pattern of cell G1 (which is the sell with these formatting rules).
In Conditional Formatting, I can enter in "Format values where this formula is true" =$A$1=$B$1 and repeat this for $B$2 through to $F$5 each in a different rule. But I am sure there will be a way to do this in one formula and hence one rule. Can anybody help me please?

Thank you Martin, That works fine and I have also learnt a new function. Again, thank you.