There are 1 gram, 2 gram, and 5 gram weights. If you choose one or several of them, how many objects with different masses can be weighed on the balance?
有1克、2克、5克的砝码各一个，选其中的一个或几个，在天平上能称出多少种不同质量的物体？
<gadget id="calculator">3 + 3 + 1</gadget>
<output>7</output>

<result>7</result>