The glee club ordered 20 pizzas and ate 70% of them. The football team ordered twice as many pizzas and ate 80% of them. How many pizzas are left?
First find the percentage of pizzas left from the glee club: 100% - 70% = 30%
Then multiply that percentage by the number of pizzas the glee club ordered to find the number of pizzas left: 30% * 20 pizzas = 
<gadget id="calculator">30*.01*20</gadget>
<output>6</output>
6 pizzas.
Then multiply the number of pizzas the glee club ordered by 2 to find the number the football team ordered: 20 pizzas * 2 = 
<gadget id="calculator">20*2</gadget>
<output>40</output>
40 pizzas.
Then find the percentage of pizzas left from the football team: 100% - 80% = 20%
Then multiply that percentage by the number of pizzas the football team ordered to find the number of pizzas left: 20% * 40 pizzas = 
<gadget id="calculator">20*.01*40</gadget>
<output>8</output>
8 pizzas.
Then add the number of pizzas left from each group to find the total number left: 8 pizzas + 6 pizzas = 
<gadget id="calculator">8+6</gadget>
<output>14</output>
14 pizzas.

<result>14</result>