프로그래머스 - 숫자 문자열과 영단어 [81]
https://programmers.co.kr/learn/courses/30/lessons/81301
https://programmers.co.kr/learn/courses/30/lessons/81301
정보처리기사 필기
https://programmers.co.kr/learn/courses/30/lessons/77484?language=javascript
https://programmers.co.kr/learn/courses/30/lessons/17676
https://programmers.co.kr/learn/courses/30/lessons/42888