Every year, Mabel gets as many quarters as she is years old. She always puts these and nothing else in a piggy bank. When she turns 7, how much money is in the bank?
On her second birthday she adds $.5 because 2 x .25 = 
<gadget id="calculator">2*.25</gadget>
<output>0.5</output>
.5.
On her third birthday she adds $.35 because 3 x .25 = 
<gadget id="calculator">3*.25</gadget>
<output>0.75</output>
.75.
On her fourth birthday she adds $1 because 4 x .25 = 
<gadget id="calculator">4*.25</gadget>
<output>1</output>
1.
On her fifth birthday she adds $1.25 because 5 x .25 = 
<gadget id="calculator">5*.25</gadget>
<output>1.25</output>
1.25.
On her six birthday she adds $1.5 because 6 x .25 = 
<gadget id="calculator">6*.25</gadget>
<output>1.5</output>
1.5.
On her seventh birthday she adds $1.75 because 7 x .25 = 
<gadget id="calculator">7*.25</gadget>
<output>1.75</output>
1.75.
The total is $7 because .25 + .5 + .75 + 1 + 1.25 + 1.5 + 1.75 = 
<gadget id="calculator">.25+.5+.75+1+1.25+1.5+1.75</gadget>
<output>7</output>
7.

<result>7</result>