Explanation:
In order to balance a chemical equation, it is required that the number of reactant atoms or molecules should equal the number of product atoms or molecules.
For this, we first of all write the chemical formulas and symbols on both reactant and product side. Then we count the number of individual atom on the reactant and product side followed by multiplication or division of according to the count of respective atom.
For example, 
Here the number of nitrogen atoms on reactant side should be equal to the number of nitrogen atoms on product side. Similarly, the number of hydrogen atoms on reactant side should be equal to the number of hydrogen atoms on product side. Only then this equation will be balanced.
Therefore, we can conclude that out of the given options, the statements which are not true are as follows.
- Subtract the total amount of elements from the products.
- Add all the elements together.