If $$6$$ hoots $$=3$$ hollers, then $$10$$ hollers $$=$$~\uline{~~~~~~~~~~}~hoots. 
Overseas Competition->Knowledge Point->Calculation Modules->Basic Concepts of Equation->Equivalent Substitution->Algebraic Expressions
If $$2$$ hoots $$=1$$ holler, then $$(10\times 1)$$ hollers $$=(10\times 2)$$ hoots. 