What is the chemical equation for: hot iron reacts with hot steam to form iron(II,III) oxide and hydrogen gas is released?

Iron(II,III) oxide has the formula  Fe_3O_4, and water steam has the same formula as water, H_2O. Therefore the unbalanced equation has the form
Fe + H_2O =Fe_3O_4 + H_2.
To balance this equation, first look at  Fe: one at the left and 3 at the right. So give Fe at the left the coefficient 3. It becomes
3Fe + H_2O = Fe_3O_4 + H_2.
Then count oxygen O: 1 at the left side and 4 at the right side. Thus give H_2O at the left the coefficient 4:
3Fe + 4H_2O = Fe_3O_4 + H_2.
And finally take into account hydrogen H: 8 at the left, 2 at the right. So it is enough to give the coefficient 4 to H_2:
3Fe + 4H_2O = Fe_3O_4 + 4H_2.
Now the equation is balanced.
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