Tina has 12 pink pens. She has 9 fewer green pens than pink pens. Tina has 3 more blue pens than green pens. How many pens does Tina have in total?
Tina has 12 - 9 = 
<gadget id="calculator">12-9</gadget>
<output>3</output>
3 green pens.
Tina has 3 + 3 = 
<gadget id="calculator">3+3</gadget>
<output>6</output>
6 blue pens.
In total Tina has 12 + 3 + 6 = 
<gadget id="calculator">12+3+6</gadget>
<output>21</output>
21 pens.

<result>21</result>