There are 1 gram, 2 gram, and 4 gram weights each. Choose one or more of these 3 weights, and how many different weights can be weighed.
有1克、2克、4克的砝码各一个，在这3个砝码当中选出1个或几个使用，可以称出多少种不同的重量．
<gadget id="calculator">3 + 3 + 1</gadget>
<output>7</output>

<result>7</result>