Try:
4Fe + 3O2 → 2Fe2O3
4 × Fe3 × O2→2 × Fe2O3
How it works
Balancing an equation means finding whole-number coefficients so the same number of atoms of every element appears on both sides. This solver treats that as a system of linear equations — one equation per element — and finds its solution space using exact fraction arithmetic (not floating-point, which can silently round off equations that need larger coefficients), then scales the result to the smallest whole numbers. Every result is re-verified against the original formulas before being shown.
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