3.3.3 Counting with Bijections: Video

MIT 6.042J Mathematics for Computer Science, Spring 2015
Instructor: Albert R. Meyer

License: Creative Commons BY-NC-SA

[darshan]

6:03 It should be (9*10^3) - ( 8*9^3 ) since the thousandth place can't be zero given it's a four digit number

[mrboyban]

Tasty flavoursome masterclass teaching. Thanks!

[jonathansum]

why is n-1? Isn't it N because the length is n?

[chaitanyavig]

Technically, a four digit number cannot start with '0'

[veggiekeller]

You're calculating the possibility of at least 1 7 at 3:30, but you seem to be calculating the possibility of exactly 1 7.