Beau’s sons are triplets.  They are 16 years old today.  Three years ago, the sum of his 3 sons’ ages equaled Beau’s age.  How old is Beau today?
Three years ago, his sons were 16 - 3 = 
<gadget id="calculator">16-3</gadget>
<output>13</output>
13 years old.
Three years ago, Beau was 13 + 13 + 13 = 
<gadget id="calculator">13+13+13</gadget>
<output>39</output>
39 years old.
Today, Beau is 39 + 3 = 
<gadget id="calculator">39+3</gadget>
<output>42</output>
42 years old.

<result>42</result>