Tom's cat needs an expensive surgery.  He has had pet insurance for 24 months that cost $20 per month.  The procedure cost $5000 but the insurance covers all but 20% of this.  How much money did he save by having insurance?
The insurance cost 24*20=$
<gadget id="calculator">24*20</gadget>
<output>480</output>
480.
With insurance he pays 5000*.2=$
<gadget id="calculator">5000*.2</gadget>
<output>1_000</output>
1000 for the procedure.
So he paid 1000+480=$
<gadget id="calculator">1000+480</gadget>
<output>1_480</output>
1480.
So he saved 5000-1480=$
<gadget id="calculator">5000-1480</gadget>
<output>3_520</output>
3520.

<result>3_520</result>