Al(s) +
Fe2O3(s)
Fe(s) + A1,0.3)
PER nuctives

2
A
l
+
F
e
2
O
3

→

A
l
2
O
3
+
2
F
e

Explanation:
One must first balance the metals before balancing non-metals such as Oxygen and Hydrogen (Hydrogen isn't involved in this case).
So therefore on the right hand side you see 2 Aluminium atoms and thus one must add a 2 before the Aluminium on the left hand side.
Secondly the Iron must be balanced, on the left it can be seen that there are 2 Iron atoms in
F
e
2
O
3
and thus a 2 must be added on the right hand side in order for them to balance.
Lastly the Oxygens must be balanced but in this case they already are at 3 on each side and thus the whole equation is now balanced.
Hope I helped :)