John earned 50 dollars an hour and worked 6 hours in the week.  If he spends 50 dollars on gas and wants to deposit 100 dollars in the bank, how many 25 dollar pens can he buy after he buys 5 pencils that cost 10 dollars each?
He earned $50*6=$
<gadget id="calculator">50*6</gadget>
<output>300</output>
300.
He has $300 - $100 = $
<gadget id="calculator">300-100</gadget>
<output>200</output>
200 to spend.
He spends 5 * $10 = $
<gadget id="calculator">5*10</gadget>
<output>50</output>
50 on pencils.
After buying gas and pencils he has $200 - $50 - $50 = $
<gadget id="calculator">200-50-50</gadget>
<output>100</output>
100 to spend on pens.
He can buy $100/25=
<gadget id="calculator">100/25</gadget>
<output>4</output>
4 pens.

<result>4</result>