So all you have to do is balance them
For example we have KNO3___KNO2+O2 so you have to balance them first of all see how many K are there there is only 1 in the reactant so then see how many OxygenIn first recatant is 2 and in second one is also 2 so add them it’s 4 now we have KNO3_____KNO2+O4 now we have 4 oxygen we need to make KNO4 so add 1 it will be Balanced! That’s all I hope you understood