Add 12 to the number if it is a number field.
UPDATE SomeTable
SET SomeField = SomeField + 12
WHERE SomeField = 1.75
Just replace the value
UPDATE SomeTable
SET Somefield = 13.75
WHERE SomeField = 1.75
If the field is text
UPDATE SomeTable
SET Somefield = "13.75"
WHERE SomeField = "1.75"
This is so simple, that obviously you must have something more complex
that just changing 1.75 to 13.75. However, from your stated question
there is really no good way to know what you want to do in a more
general sense.
'====================================================
John Spencer
Access MVP 2002-2005, 2007-2009
The Hilltop Institute
University of Maryland Baltimore County
'====================================================