Archie needs to lay sod in his backyard that measures 20 yards by 13 yards. He has a shed on it that measures 3 yards by 5 yards. How many square yards of sod will Archie need for his backyard?
20 * 13 = 
<gadget id="calculator">20*13</gadget>
<output>260</output>
260 square yards
3 * 5 = 
<gadget id="calculator">3*5</gadget>
<output>15</output>
15 square yards
260 - 15 = 
<gadget id="calculator">260-15</gadget>
<output>245</output>
245 square yards.
Archie needs 245 square yards of sod.

<result>245</result>