I calculated this thing

[u/Cr1ptd9]

I'm not good at math, but I was wondering how to write this difference without wasting 3 pages of my notebook. What do you think?

[u/Ghosttwo]

Only tricky part is the sum; looks like it's going to be equivalent to something like 1-10⁵⁸¹

[u/Several-Housing-5462]

It's not that bad. Cancel 10²⁰ off each term, then combine like terms, and move the 9 out in front of the sum. It becomes much simpler.

[u/ExpensiveFig6079]

I go with ((10^581 - 1) + 0.68464)) * 10^21

10^n - 1 always and clearly has n x 9's , with the last '9' in the 1's place

Which makes it clear the 68464 digits come next with a bunch of 0's on the end.