Martha receives a daily allowance of $12. She decides to save half of this amount every day. In the first week she kept her commitment with the exception of one day when she saved only a quarter of this amount. How much has she saved at the end of this week?
Half of $12 is (1/2)*$12 = $6.
There are 7 days in a week so if she saved half every day except one then she saved half for 7-1 = 
<gadget id="calculator">7-1</gadget>
<output>6</output>
6 days.
She saved $6 for 6 days for a total of $
<gadget id="calculator">6*6</gadget>
<output>36</output>
36.
A quarter of $12 is (1/4)*$12 = $
<gadget id="calculator">12*1/4</gadget>
<output>3</output>
3.
She saved a quarter once for a total savings of $3+$36 = $
<gadget id="calculator">3+36</gadget>
<output>39</output>
39.

<result>39</result>