Paul makes pencils, making 100 pencils a day five days a week. He started the week with 80 pencils in his stock, and during the week he sold 350 pencils. How many pencils did he have in his stock at the end of the week?
Making 100 pencils a day, he made 100 pencils/day * 5 days/week = 
<gadget id="calculator">100*5</gadget>
<output>500</output>
500 pencils during the week.
With the pencils from the stock, he got 500 pencils + 80 pencils = 
<gadget id="calculator">500+80</gadget>
<output>580</output>
580 pencils.
Subtracting the ones he sold, he has 580 pencils - 350 pencils = 
<gadget id="calculator">580-350</gadget>
<output>230</output>
230 pencils.

<result>230</result>