Mark got a 5% raise at his job.  Before the raise, he earned 40 dollars per hour.  He works 8 hours per day for 5 days per week.  His old bills used to be 600 dollars a week but he decided to add a hundred dollar a week personal trainer.  How much does he have leftover a week?
After the raise he earns 40*1.05=
<gadget id="calculator">40*1.05</gadget>
<output>42</output>
42 dollars an hour.
He works 8 hours per day so earns 42*8=
<gadget id="calculator">8*42</gadget>
<output>336</output>
336 per day.
He works 5 days per week so he earns 336*5=
<gadget id="calculator">336*5</gadget>
<output>1_680</output>
1680 a week.
His expenses after adding the personal trainer are 600+100=
<gadget id="calculator">600+100</gadget>
<output>700</output>
700 a week.
So he has 1680-700=
<gadget id="calculator">1680-700</gadget>
<output>980</output>
980 left over.

<result>980</result>