# TABULA/samples/convert quantity

## To update a given item

Suppose the item to be updated is line {1}.

• Click line {1} to select it.
the item's value is echoed in the input field, and the item's units are shown in the units dropdown, together with any compatible units which TABULA knows about.
• Edit/replace the data in the input field.

### Examples of acceptable inputs to update the given item

Suppose line {1} is currently: 1 m

• 6 m
—changes: 1 m to: 6 m
• 6
—changes 1 m to: 6 m
if you don't want to change the units, then  m is superfluous.
• [ft]
—changes: 1 m to: 3.281 ft
i.e. 1 metre, converted to feet
• 18 [ft]
—replaces the entire quantity (i.e. both value and units) with: 18 ft .
• 18 [kg]
—leaves the line unaltered and displays the error message:
>>> incompatible units: [m][kg]

## How to create a new line showing any desired quantity

Suppose you want your new line (say {2}) to show the quantity: 2.34 ft/s

If you omit brackets […] round the units, then TABULA takes: 2.34 ft/s to represent a quantity, which is to be preserved as a quantity and converted to SI units (the default units for that given quantity).

TABULA does not signal: >>> incompatible units: … because the quasi-unit [*] is compatible with any units.