Frank is making hamburgers and he wants to sell them to make $50.  Frank is selling each hamburger for $5 and 2 people purchased 4 and another 2 customers purchased 2 hamburgers.  How many more hamburgers does Frank need to sell to make $50?
Frank sold 4 hamburgers and then sold 2 more, so all together Frank already sold 4+2= 
<gadget id="calculator">4+2</gadget>
<output>6</output>
6 hamburgers.
If each hamburger is $5 and he sold 6 hamburgers already, Frank has made 5*6= 
<gadget id="calculator">5*6</gadget>
<output>30</output>
30 dollars.
Frank wants to make $50 and has already made $30, so Frank still needs 50-30= 
<gadget id="calculator">50-30</gadget>
<output>20</output>
20 dollars.
Since he needs $20 and each hamburger is $5, Frank needs to sell 20/5= 
<gadget id="calculator">20/5</gadget>
<output>4</output>
4 more hamburgers.

<result>4</result>