A balance has 1 gram, 2 gram, 4 gram, 8 gram and 16 gram each, how many different masses can be weighed on the balance with these weights (the weight is only placed on the right side of the balance ).
一架天平有1克、2克、4克、8克和16克的砝码各一个，用这些砝码一共可以在天平上称出多少种不同的质量(砝码只放在天平的右侧)．
<gadget id="calculator">1 + 2 + 4 + 8 + 16</gadget>
<output>31</output>

<result>31</result>