Aron spends 30 minutes/day three times a week vacuuming and 20 minutes/day 2 days a week dusting. How much time does he spend cleaning total each week?
First find the total time Aron spends vacuuming: 30 minutes/day * 3 days/week = 
<gadget id="calculator">30*3</gadget>
<output>90</output>
90 minutes/week.
Then find the total time Aron spends dusting: 20 minutes/day * 2 days/week = 
<gadget id="calculator">20*2</gadget>
<output>40</output>
40 minutes/week.
Then add those two times to find Aron's total cleaning time per week: 90 minutes/week + 40 minutes/week = 
<gadget id="calculator">90+40</gadget>
<output>130</output>
130 minutes/week.

<result>130</result>