Metals which react with steam form the solid metal oxide and hydrogen gas.
In general, the more reactive the metal, the more rapid the reaction. Aluminium is unusual, because it is a reactive metal that does not react with water. Its surface forms a protective layer of aluminium oxide that keeps water away from the metal below.
The apparatus used to react a metal with steam and collect the gas produced is shown below.
This is because some metals like aluminium, zinc, iron do not react with hot/cold water ; they react only with steam to form a metal oxide and hydrogen.
First you add all the numbers together. So you add 82+93+75+89 to get 339. Once you get that, you divide it by the amount of numbers there are. In this case, it's 4. 339 divided by 4 is 84.75.