Balancing chemical equations

• balance this equation:

  Na + I2 ➡️ NaI

  2Na + I2 ➡️ 2NaI
• Fe2O3 + 3CO ➡️ 2Fe + CO2

  Fe2O3 + 3CO ➡️ 2Fe + 3CO2
• CaO + HCl ➡️ CaCl2 + H2O

  CaO + 2HCl ➡️ CaCl2 + H2O