Kim's TV uses 125 watts of electricity per hour.  She runs it for 4 hours a day.  If electricity cost 14 cents per kw/h how many cents does her TV cost to run for a week?
She uses 4 hours/day * 125 watts/hour=
<gadget id="calculator">4*125</gadget>
<output>500</output>
500 watt hours/day.
That means she uses 500 watt hours/day * 7 days/week = 
<gadget id="calculator">500*7</gadget>
<output>3_500</output>
3500 watt hours/week.
This is 3500 watt hours / 1000 watts/kw = 
<gadget id="calculator">3500/1000</gadget>
<output>7/2 = around 3.5</output>
3.5 kw hours.
So her TV cost 3.5 kw hours/week * $0.14/kw hour = $
<gadget id="calculator">3.5*0.14</gadget>
<output>0.49</output>
0.49/week.

<result>49</result>