Multi-purpose natural language calculator

Scans a natural language input and evaluates any valid mathematical expression found.

It can be used for many applications:

• Basic arithmatic:
  eg: "5 + 450"
  eg. “90k - 10%”

• Calendar calculations (working out dates & times)
  Eg. "March 12 + 3 weeks"
  Eg. "7:45am + 2 hours 25 minutes"
  Eg. “July 30 to August 20 in days”

• Time zone conversions
  Eg. "time in Tokyo"
  Eg. "time difference between Chicago and Sydney"
  Eg. “10am Paris to Auckland”

• Financial & percentage functions:
  Eg: "25% of 900"
  eg. "50 is 30% of what"
  eg. “$50k over 5 years at 7%” (compound interest)

• Unit conversions:
  eg. "59 kg in pounds"
  eg. “300 miles/hour in km/hour”

• Currency conversions (166 real-world currencies + 20 popular crypto-currencies supported):
  eg. "20 USD in AUD"
  eg. “50 Bitcoin in Euros”

• Many other helpful functions:
  eg: "random number between 10 and 25"
  eg. “5 is to 50 as what is to 100” (answer = 10)
  eg. “November 12 3:30pm as timestamp” (answer = 1605155400)