Create a TypeScript file calculator.ts that exports add, subtract, multiply, divide functions (divide should throw on zero). Then write a tests file calculator.test.ts using node:test that covers all four. Run the tests with 'node --test --experimental-strip-types calculator.test.ts' and show the output. Finally, edit calculator.ts to also export a 'modulo' function and re-run the tests (don't add a test for modulo, just check the existing tests still pass).