Felix is chopping down trees in his backyard. For every 13 trees he chops down he needs to get his axe resharpened. It cost him $5 to sharpen his axe. If he spends $35 on axe sharpening, at least how many trees has he chopped down?
He has sharpened in 7 times because 35 / 5 = 
<gadget id="calculator">35/5</gadget>
<output>7</output>
7.
He has chopped down 91 trees because 7 x 13 = 
<gadget id="calculator">7*13</gadget>
<output>91</output>
91.

<result>91</result>