Use this formula instead.
Formula
=ARRAYFORMULA(IFERROR(A2:A/B2:B))
Note
Error catching has to take place inside the ARRAYFORMULA
Use this formula instead.
Formula
=ARRAYFORMULA(IFERROR(A2:A/B2:B))
Note
Error catching has to take place inside the ARRAYFORMULA
Just for completeness:
In C2 you can write:
=A2/B2
then copy the cell (CTRL-C) and paste it (CTRL-V) to the whole column where you want the result to be visible. This will procude the same result as ARRAYFORMULA() and is in general more effort, but allows you to select the rows where you want to have the result.
Alternatively you can also provide the last row you want to calculate over to arrayformula.
=ARRAYFORMULA(A2:A27/B2:B27)
This would only print in lines 2-27.
I would like to split the cells underneath a column heading. How can I split a cell in sheets please - Google Docs Editors Community
excel - Dividing whole column in Google Spreadsheet - Stack Overflow
how do you split cells in google sheet - Google Docs Editors Community
How do I make Google Spreadsheet automatically divide a column into another column? - Stack Overflow
The word you are looking for is called cell reference in Excel or spreadsheet lingo.
Use the formula =DIVIDE($A1,5) and drag the cell handle down across all the cells. Here is my sample.
When I dragged the first cell to the end, this is what google spreadsheet did
Result with values

why not:
=INDEX(IFERROR(A1:A/5; 0)