Add a character to numerous rows

Hi all,

Bit of a newbie to Excel, so apologise in advance!!

I have a spreadsheet that contains 300+ rows of info. I exported data from an application to a .csv file. The first column has mobile telephone numbers but all are missing the first Zero eg 7809xxxxxx

I was wondering if someone could help me to add the zero automatically rather than go through it manually.

Thanks
Rob.

If you just want the view of the data to change and all numbers are 11 digits Including the missing zero) you could just format the cells as

00000000000

or with a formula, assuming your numbers are in A1:A300 use this formula in B1 copied down

=0&A1

then you can convert column B to values,

Select Column > Edit > Copy > Edit > Paste Special > Values > OK

now delete column A

Great stuff, worked a treat.

Thanks again,
Rob.