Showing names assigned to phone numbers

[Jaime González Benedet]

I have entered in the cells A1:B10 numbers in column A, and names in
the column B.

In the range A20:A25 there are six phone numbers and I want Excel to
show -if the number does exist- the names in the cells B20:B25 or -if
not- an empty string

I was trying the array formula:

{=IF(A20=$A$1:$A$10;$B$1:$B$10;"")}

written in the cell B20 to -if worked- be then copied and pasted on
the following B21:B25 cells.

But doesn't work. Is the first time I tried an array formula.

Could somebody tell me how to do it?

Thanks
Jaime
Oviedo-Spain