add safe math fns

[brunobar79]

Fixes APP-####

What changed (plus any additional context for devs)

Wrote basic math functions to safely deal with big numbers operations without any extra dependency (so it can be used in worklets).

Added tests including comparing results with BigNumber.js library which we know it's accurate

Screen recordings / screenshots

What to test

[christianbaroni]

Thoughts on adding validation given the broadness of the string type? Something like:

const isNumberString = (value: string): boolean => {
  return /^\d+(\.\d+)?$/.test(value);
};