There are 1 gram, 2 gram, 4 gram, and 8 gram weights. Choose two weights each time from these four weights. How many different masses can be weighed? (Weights can also be placed on both sides of the balance)
有1克、2克、4克、8克的砝码各一个，从这四个砝码中每次任选两个砝码使用，能称出几种不同的质量？(砝码也可以放在天平的两边)
<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<result>10</result>