Forum:Mathmech Equip + Damage Calculation rulings

Hello, i have a ruling question concerning primarily the equip spell Mathmech Billionblade Nayuta, and secondarily cards like Mathmech Division. For the example, let's say Player A has a 5000 ATK monster, say FGD. Player B has Geomathmech Final Sigma equipped with Billionblade. FGD declares an attack on the synchro cyberse. During damage calculation, the equip effect is activated, and sends Division from the deck to the graveyard. Two questions:

1 - Minor: Division was sent to the GY as a cost; If player B chooses to activate its ATK halving effect on FGD, does said effect activate in a SEPARATE chain after the spell increases the ATK of the synchro by 1000 atk?

2 - Major: This question applies assume the answer to 1 is "Yes" (aka Division effect resolves in a separate chain); which happens / resolves first? Does the 5000 ATK FGD destroy Final Sigma by battle, THEN Division's effect activates and makes it 2500 atk? Or during the same damage calculation, does Division weaken FGD BEFORE the battle happens, so Final Sigma manages to destroy FGD by battle?

Any details as to why X happens are welcome.

Thank you in advance for reading, and answering. Imadmagician (talk • contribs) 17:14, 22 December 2019 (UTC)

Cards and effects that are activated in response to battle during damage calculation can only be activated on the 1st Chain during that damage calculation.

However, this does not mean that only 1 Chain can be created during damage calculation. Any number of Chains can be created as usual.

During that damage calculation,

CL1: You send 1 Mathmech Division from your Deck to the GY to activate Mathmech Billionblade Nayuta's Trigger-like Effect.

CL1 resolves: That Geomathmech Final Sigma gains 1500 ATK until the end of that turn.

-After this Chain has resolved, that Mathmech Division has been sent to the GY, so you can activate its Trigger Effect on a new Chain. There is nothing special about this happening during damage calculation.

CL1: You activate Mathmech Division's Trigger Effect in your GY, then targets that face-up battling monster your opponent controls.

CL1 resolves: Its ATK becomes halved until the end of that turn.

When actual damage calculation is performed, that opponent's monster is determined to be destroyed by battle later, and battle damage is inflicted to your opponent.

At the end of that Damage Step, that monster is destroyed by battle and leaves the field. - HHT   20:27, 22 December 2019 (UTC)