AI solution for JavaScript Quiz on BFE.dev
95. number format

The code below outputs:

4
7
8

Note that numbers with a leading 0 in JavaScript are interpreted as octal (base 8) numbers. Therefore, 017 is equal to 1*(8^1) + 7*(8^0) which is equal to 15, and 011 is equal to 1*(8^1) + 1*(8^0) which is equal to 9. So 017 - 011 is equal to 15 - 9 which is equal to 6 in decimal (base 10).

However, 018, 019, and so on are not valid octal numbers, so they are interpreted as decimal numbers. Therefore, 018 is equal to 18 and 019 is equal to 19, so 018 - 011 is equal to 18 - 9 which is equal to 9, and 019 - 011 is equal to 19 - 9 which is equal to 10.