C6H12O6 + O2 > CO2 + H2O

C6H1206 + 6O2 > 6CO2 + 6 H2O

Explanation:

On the left side we have 6xC so we multiply CO2 by 6 to get the same amount of C.

We have 12x H on the left side, so we multiply H2O on the right side by 6 to get the same amount of H.

On the right side we have 18x O (6CO2 gives us 6x2x O which is 12O; and 6H2O gives us 6O. To get the same amount on the left side (we already have 6O in C6H12O6), so we only need 12 O more. So we multiply O2 on the left side by 6. Which gives us 18x O on both sides.

So on both sides we have now:

6x C

12xH

18xO