Cool Math Games Jacksmith [top] -

This is the active phase. You have a limited amount of time to craft weapons for your soldiers. You must mine ore, smelt it, shape the weapon, and attach a handle/guard.

While not math-drill based, Jacksmith develops several learning skills: cool math games jacksmith

If you are short on materials (e.g., only enough Steel for two swords out of three troops), give the Steel sword to the unit in the (the one taking the most damage). The back-line units take less damage, so they can survive with Copper/Iron weapons. This is the active phase