|Simply add 1 to each date to increment it by 1.|
With 01/02/12 in A1, =A1+1 will return 01/03/2012
Excel stores dates and times in what is known as a "serial number" which represents the number of days (or parts thereof) since 1/1/1900.
As you increment that serial number by 1, you are adding one more day since 1/1/1900.
If you increment that serial number by 0.5, you'll increment that date by 12 hours, or half a day.
To prove this to yourself, enter =NOW(). You'll should see the current date and time.
Now format that cell as a number and you'll see something like 40917.86.
For more on using Dates & Times in Excel, see this site:
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