Don buys recyclable bottles in a small town. Shop A normally sells him 150 bottles, shop B sells him 180 bottles and Shop C sells him the rest. How many bottles does Don buy from Shop C if he is capable of buying only 550 bottles?
Between Shop A and Shop B he buys 150 bottles+180 bottles=
<gadget id="calculator">150+180</gadget>
<output>330</output>
330 bottles.
Thus he can buy 550 bottles-330 bottles=
<gadget id="calculator">550-330</gadget>
<output>220</output>
220 bottles from shop C.

<result>220</result>