calculating-with-functions.js

// seven(times(five())); // must return 35
// four(plus(nine())); // must return 13
// eight(minus(three())); // must return 5
// six(dividedBy(two())); // must return 3

const zero = (operation) => !operation ? 0 : operation(0);
const one = (operation) => !operation ? 1 : operation(1);
const two = (operation) => !operation ? 2 : operation(2);
const three = (operation) => !operation ? 3 : operation(3);
const four = (operation) => !operation ? 4 : operation(4);
const five = (operation) => !operation ? 5 : operation(5);
const six = (operation) => !operation ? 6 : operation(6);
const seven = (operation) => !operation ? 7 : operation(7);
const eight = (operation) => !operation ? 8 : operation(8);
const nine = (operation) => !operation ? 9 : operation(9);

const plus = (number) => (other_number) => other_number + number;
const minus = (number) => (other_number) => other_number - number;
const times = (number) => (other_number) => other_number * number;
const dividedBy = (number) => (other_number) => other_number / number;

console.log(seven(times(five())), 35); // must return 35
console.log(four(plus(nine())), 13); // must return 13
console.log(eight(minus(three())), 5); // must return 5
console.log(six(dividedBy(two())), 3); // must return 3