Lovely cuts her birthday cake into 12 equal pieces. Only one-fourth of the cake was eaten by her visitors and the rest were kept. How many slices of cake were kept?
12/4 = 
<gadget id="calculator">12/4</gadget>
<output>3</output>
3 slices of cake were eaten by Lovely's visitors.
So, 12 - 3 = 
<gadget id="calculator">12-3</gadget>
<output>9</output>
9 slices of cake were kept.

<result>9</result>