Actually, never mind. I just realized that Prof. Loh just explained it in the next part.

@FoxInABush

Maybe your keyboard doesn't work, or something's wrong on your end.

I think it's because the Week 3 Challenge is not a Prerequisite.

@inventiveantelope Doesn't really matter.

@smilingtadpole-1 In this problem, we do not care whether 11 has one or two 1s. What matters is the fact that 11 contains a 1. When you solved this problem, you assumed that because 11 had two ones, it should be counted twice, which is incorrect. I hope this helps!(also charge your device lol)

@RZ923
Yeah! A lot of times in math using ideas in geometry may help, just like the hockey stick identity! You can flip the point of the stick to the other to make it symmetrical.

uhhh i play minecraft, genshin impact, and roblox (if my friend is forcing me too)
on my phone i play cookie run kingdom