Roger had a 6-hour drive planned out.  He didn't want to listen to music so he downloaded several podcasts.  The first podcast was 45 minutes long.  The second podcast was twice as long as that.  The third podcast was 1 hour and 45 minutes long.  His fourth podcast is 1 hour long.  How many hours will his next podcast have to be to fill up the full 6 hours?
The second podcast was twice as long as the first so 2*45 = 
<gadget id="calculator">2*45</gadget>
<output>90</output>
90
1 hour is 60 mins. So his 1 hour and 45 min podcast is 60+45 = 
<gadget id="calculator">1*60+45</gadget>
<output>105</output>
105 minutes long.
So far he has downloaded 45+90+105+60 = 
<gadget id="calculator">45+90+105+60</gadget>
<output>300</output>
300 min.
If he converts 300 min to hours then he has 300/60 = 
<gadget id="calculator">300/60</gadget>
<output>5</output>
5 hours of podcasts downloaded.
He has 5 hours of podcasts and his drive is 6 hours so he will need 6 - 5 = 
<gadget id="calculator">6-5</gadget>
<output>1</output>
1 more hour of podcasts.

<result>1</result>