Erica made 20 Valentine's cards to pass out.  Her dad brought her 2 boxes of pre-made Valentine's cards that had 15 cards each.  She passed out 24 to her classmates, 5 to her family and received 17 from family and friends.  How many Valentine's Day cards does Erica now have?
Her dad gave her 2 boxes of 15 cards so 2*15 = 
<gadget id="calculator">2*15</gadget>
<output>30</output>
30.
She made 20, was given 30 and received 17 so 20+30+17 = 
<gadget id="calculator">20+30+17</gadget>
<output>67</output>
67 cards.
She passed out 24 and gave 5 cards to family and friends so she gave away 24+5 = 
<gadget id="calculator">24+5</gadget>
<output>29</output>
29 cards.
She had 67 cards and gave away 29 cards so 67-29 = 
<gadget id="calculator">67-29</gadget>
<output>38</output>
38 cards left.

<result>38</result>