42 raspberries, blackberries, and blueberries were picked in total. If half of all the berries had been raspberries, and a third of the berries were blackberries, how many of them were blueberries?
42/2 = 
<gadget id="calculator">42/2</gadget>
<output>21</output>
21 raspberries had been picked.
42/3 = 
<gadget id="calculator">42/3</gadget>
<output>14</output>
14 blackberries had been picked.
21+14 = 
<gadget id="calculator">21+14</gadget>
<output>35</output>
35 raspberries and blackberries had been picked.
42-35 = 
<gadget id="calculator">42-35</gadget>
<output>7</output>
7 blueberries had been picked.

<result>7</result>