There are 50 children at the party. Three-fifths of them are boys. How many of the children are girls?
50 x 3/5 = 
<gadget id="calculator">50*3/5</gadget>
<output>30</output>
30 children are boys.
So, there are 50 - 30 = 
<gadget id="calculator">50-30</gadget>
<output>20</output>
20 children that are girls.

<result>20</result>