Come up with five common objects that, when you change the subscript in their “formula,” you can then show that what you have is no longer the same as what you started with. For example, the formula for a bicycle is frame₁tires₂. If you were to change the subscript to frame₂tires₂, would it still be a bicycle, or something else? How does this relate to changing the subscripts in a chemical formula? Then develop a rule that says when you can change the subscripts in a chemical formula while balancing a chemical equation.