See: https://www.typescriptlang.org/play?#code/C4TwDgpgBAwgThAhsCBBOdEgDwDUoQAeKAdgCYDOUJArgLYBGEcANFOnAcROVTSQGsSAewDuJANoBdKAF4o0gHxyAUFHXsMXUpSgBvKABseAc2AALAFxR8AXygB+TXGvwkKDljxsJAOn8cbACMUooA3CoqoJDsZGTYqNo8urSMzGwAQkm81PRMcMryfv5uyGgYXqiKbP6+pR4VOBmKUhIA5MYkZuZtUhFR4ND48qhx2ABMbADM4ZHR0ADKNAwJ2Sl56VBZRDpUqfmFsAhlnjhVa1TFdccNmE3VULUAliQAZs…

generic-maths-in-ts.ts

type CreateArray<V extends number, Arr extends unknown[] = []> =
    Arr extends { length: V } ? Arr: CreateArray<V, [...Arr, 1]>;

type Add<A extends number, B extends number> = [...CreateArray<A>, ...CreateArray<B>]['length'];

type V = Add<2, 3>;

type Sub<A extends number, B extends number> = CreateArray<A> extends [...CreateArray<B>, ...infer Els] ? Els['length'] : never;

type V2 = Sub<10, 1>;

type Mul<A extends number, B extends number, Arr extends unknown[] = []> =
    CreateArray<B> extends { length: 0 } ? Arr['length'] : CreateArray<B> extends [1, ...infer Els] ? Mul<A, Els['length'], [...Arr, ...CreateArray<A>]> : never;

type V3 = Mul<3, 7>;

Might be fun to do some other operations (Div, Mod etc), and to explain conceptually what is going on. Perhaps also to take a look at whether other people have achieved this in a worse or better way?

See: https://github.com/grantila/meta-types