On a 16 GB (gigabyte) capacity USB drive, 50% is already busy. Calculate the number of gigabytes still available.
We calculate 50% of 16 GB:
50/100 * 16 GB = 0.5 * 16 GB = 
<gadget id="calculator">50/100*16</gadget>
<output>8</output>
8 GB.
That leaves 16 GB - 8 GB = 
<gadget id="calculator">16-8</gadget>
<output>8</output>
8 GB available on this key.

<result>8</result>