Sara makes cakes during the five weekdays to sell on weekends. She makes 4 cakes a day and sells her cakes for $8. In 4 weeks she managed to sell all the cakes. How much money did she collect during that time?
During the week she makes 5 days/week * 4 cakes/day = 
<gadget id="calculator">5*4</gadget>
<output>20</output>
20 cakes.
After selling them over the weekend she earns 20 cakes * $8/cake = $
<gadget id="calculator">20*8</gadget>
<output>160</output>
160.
In 4 weeks she raised $160/week * 4 weeks = $
<gadget id="calculator">4*160</gadget>
<output>640</output>
640.

<result>640</result>