Multiples of 3 and 5

January 03, 2020 • ☕️ 1 min read

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

Find the sum of all the multiples of 3 or 5 below 1000.

const solutionOne = () => {
    const numberToUse = 1000;
    const numberSummer = (num: number) => {
        let multiples: number[] = [];
        for (let i = 0; i < num; i++) {
            if (i % 3 === 0 || i % 5 === 0) {
                multiples = [...multiples, i];
            }
        }
        return multiples.reduce((a, b) => a + b, 0);
    };
    return numberSummer(numberToUse);
};