How do you balance chrmical equations?

To balance chemical equations, what must be done is the same number of each element in the input must be present in the output. For example, photosynthesis.

H2O + CO2 —> C6H12O6 + O2

As can be deduced, the input only has 2 H, 1 C, and 3 O. Whereas, the output has 6 C, 12H, and 6 O. When balancing I recommend to balance the unique elements if possible (for example, H is only in one molecule on each side)

So you get 6(H2O) + 6(CO2) —> C6H12O6 + 6(O2)

Hope this helped!