# Date & Time

Every Date Math expression starts with a base date or time followed by the addition or subtraction of one or more durations.

The base date or time (from here onward) is derived from a field in a table or a function such as `now()` or `yesterday()` that generates datetime values.

The shorthand syntax is a unit value followed by a unit symbol. The symbols are:

* y (year)
* M (month)
* w (week)
* d (day)
* h (hour)
* m (minute)
* s (second)


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