Chemical equation

One way to show a chemical reaction is using a word equation, e.g. methane + oxygen→Carbon dioxide+water
Methane and oxygens are the reactants as they reacted together
Carbon dioxide and water are called the products as they were produced

Symbol equations are mostly used instead, they use the chemical symbol involved, e.g.
CH4+02→CO2 +H20

For an equation to be balanced, they need the same total number of each type of atom on either side of the arrow
In the equation: CH4+02→CO2 +H20
On the left, there are 1 carbon, four hydrogens and two oxygens
On the right, there are 1 carbon, two hygrogens and three oxygens

First rule of balancing is that we cannot change any of the little numbers, this is because it will create a different substance
Second rule of balancing is changing the big numbers as it represents how many of that substances there are
Final rule of balancing is that they have to be whole numbers

CH4+O2→CO2 +H20
Add two to H20 on the right side
Add two to O2 on the left side

This makes the equation:
CH4+2O2→CO2+2H20