Nelly spent ＄$$840$$ on a handbag, a wallet and a belt.  The handbag costs ＄$$300$$ more than the wallet.  The wallet costs ＄$$54$$ more than the belt.  How much did Nelly spend on the belt? 
Overseas Competition->Knowledge Point->Word Problem Modules->Questions Involving Sum, Difference and Multiples->Problems Involving Sum and Difference