You have 3 weights:1 kg,3 kg and 9 kg as well as an equal arm balance,as shown.How many different weight objects can you weigh with these three?[Remember the weights may be placed on either side] 翻譯:你有3個砝碼:1公斤、3公斤和9公斤,以及一個托盤天平,你可以稱出多少個不同的重量?(記住砝碼可以放在天邊兩邊的任意一邊)