Before I began snacking, there were $$60\div 4+1\times 3$$ gumballs here. If I ate all of them, how many gumballs did I eat? 
Overseas Competition->Knowledge Point->Calculation Modules->Whole Numbers->Mixed Operations
To evaluate $$60\div 4+1\times 3$$, we first do the $$\times $$ and $$\div $$ in the order in which they appear. Do the addition last. We get $$15+3=18$$. 