Mazie has 52 marbles and gives them to twins, Dallas and Darla.  If Dallas has a total of 21 marbles after dropping 4 of them in the playground, how many did Mazie give to Darla?
Mazie gave Dallas 21 + 4 = 
<gadget id="calculator">21+4</gadget>
<output>25</output>
25 marbles.
Darla has 52 - 25 = 
<gadget id="calculator">52-25</gadget>
<output>27</output>
27 marbles.

<result>27</result>