Michelle had some leftover cans of silly string from her birthday party. She split them among Roger and 3 of his friends. Then Roger decided to give 2 of his cans to his brothers so that he now has 4 for himself. How many cans of silly string did Michelle have to start with?
Roger originally had 4 cans of silly string + 2 can he gave to his brothers = 
<gadget id="calculator">4+2</gadget>
<output>6</output>
6 cans.
Since his friends received the same amount as Roger did originally, 3 friends x 6 cans of silly string = 
<gadget id="calculator">3*6</gadget>
<output>18</output>
18 cans.
Michelle started with 6 cans that went to Roger + 18 cans that went to his friends = 
<gadget id="calculator">6+18</gadget>
<output>24</output>
24 cans of silly string.

<result>24</result>