balance has a weight of 10 grams, a weight of 20 grams and a weight of 50 grams. How many objects of different weights can be directly weighed on the balance by using these three weights.
一架天平有10克，20克和50克的砝码各一个，用这三个砝码可以在天平上直接称出多少种不同重量的物体．
<gadget id="calculator">3 + 3 + 1</gadget>
<output>7</output>

<result>7</result>