Coefficients are numbers in front of variables. For example, in y=2x, the coefficient is 2. In the case of chemistry, the coefficient is in front if a chemical symbol and is used to balance a chemical reaction. Example: O2 + Fe= Fe2O3 (with Fe having a +3 ion) To balance use the following coefficients: 3O2+4Fe=2Fe2O3 Hope this helps!
