Mathemagic

Wizards gain power through study. Most study the relationship between the Weave, mana itself, and their ability to influence events in their material world through the manipulation of the Weave. Mathemagicians, however, are different. They gain their power and knowledge through their study of the one true universal truth: math. 

Critical Explosion

Starting at 2nd level, whenever you see a creature within 60 feet of you make an attack and roll a 20 on the attack roll, as a reaction, you can cause that creature to make an identical attack against another creature within the range of the original attack, treating it as if it had also rolled a 20 on the attack roll.

Critical Failure

Starting at 2nd level, whenever a creature rolls a 1 on a saving throw against a spell you cast with only 1 target, as a reaction, you can cause another creature within the range of the spell to be affected by the same spell, treating its saving throw as if it had also rolled a 1 on the saving throw.

Exploit Exponent

Starting at 6th level, when you roll damage for a spell and roll the highest number possible on any of the dice, roll those dice again and add those rolls to the damage. If you roll the highest number possible on any of those additional dice, repeat this process again.

You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses of it when you finish a long rest.

Decimate

Starting at 10th level, you gain the ability to use math as a weapon. As an action, you mathematically manipulate the Weave to destroy your enemies. Roll a d10. Each creature within 60 feet of you with a challenge rating equal to the number you rolled must make a Wisdom saving throw, or be instantly disintegrated. A disintegrated creature and everything it is wearing and carrying, except magic items, are reduced to a pile of fine gray dust. The creature can be restored to life only by means of a true resurrection or a wish spell.

You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses of it when you finish a long rest.

Numerical Adjustment

Starting at 14th level, whenever you or a creature of your choice within 60 feet rolls a die, as a reaction, you can spend a spell slot to increase or decrease that roll by the level of the spell slot spent. This reaction must be done before the result of the die roll is known.