Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
simplify r+(n-1)*9-(n/10**(k-1)-1)*(9*10**(k-1)-1)-(-k+2**(k+4)*5**(k-1)-9)
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random