There are 1 gram, 2 gram, and 4 gram weights each, and one or several weights are taken out of them. How many objects of different masses can be weighed in total?
有1克、2克、4克的砝码各一个，从中取出一个或几个砝码．一共可以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>