Hello,
My question is the following:
How many 8-digits number are there with their digits in decreasing order;

Headmaster

 


The digits in decreasing order are 9876543210. This forms a 10-digit number. You can form an 8-digit number with its digits in decreasing order by removing any two of the digits from 9876543210. How many ways can you choose the two digits to remove?

Penny