On Blacks, Martha goes to the mall to buy clothes on sale. For every 2 jackets she buys, she gets 1 free jacket. For every 3 t-shirts she buys, she gets 1 free t-shirt. Martha decides to buy 4 jackets and 9 t-shirts. How many clothes will she take home?
For buying 4 jackets Martha gets 4 jackets / 2 = 
<gadget id="calculator">4/2</gadget>
<output>2</output>
2 jackets for free.
For buying 9 t-shirts, Martha gets 9 t-shirts/ 3 = 
<gadget id="calculator">9/3</gadget>
<output>3</output>
3 t-shirts for free.
Adding the free jackets, Martha gets 4 jackets + 2 jackets = 
<gadget id="calculator">4+2</gadget>
<output>6</output>
6 jackets.
Adding the free t-shirts, Martha gets 9 t-shirts + 3 t-shirts = 
<gadget id="calculator">9+3</gadget>
<output>12</output>
12 t-shirts.
In total, Martha will take home 6 jackets + 12 t-shirts = 
<gadget id="calculator">6+12</gadget>
<output>18</output>
18 clothes.

<result>18</result>