Lost spreadsheet in Numbers

[Paraal]

Hi,
using Numbers on ipad3 ios8.1
Have suddenly lost a spreadsheet I have used everyday for the last 2 years, (contains daily sales figures)
Was in a folder with other spreadsheets - has disappeared from folder - other spreadsheets still in folder.
Have tried "Searching ipad" for document to no avail.
Don't think I deleted it at all.
Is this a Numbers / iCloud Problem?
How can I see a list of either deleted sheets or previous version on ipad?
More to the point how do I retrieve lost or previous version of sheet?
Any suggestions?

iPad, iOS 8.1

 

[chscag]

Have you been backing up your iPad 3 to either iCloud or your Mac? If you have, restore the sheet from backup.