How do you calculate the damage done to your opponent when monster destroys by battle in Yu-Gi-Oh?

The damage dealt to your opponent when a monster is destroyed by battle is calculated as follows:

1. Calculate the ATK of the monster that destroyed the opponent's monster.

2. Subtract the DEF of the destroyed monster from the ATK of the attacking monster.

3. If the result is a positive number, that is damage your opponent receives unless any effects prevents it.

For Example, if your monster has 1500 ATK and your opponent's destroyed monster has 1200 DEF, the damage dealt would be 1500 - 1200 =300 damage.

It's important to note that some monster effects, spell effects, and trap cards can modify or negate battle damage, so it's always essential to carefully read the card effects involved in the battle.