How many 7s are there between 1 and 1,000,000? And is there a simple formula that would give the right answer? Thanks for help.
There is a formula for such an even number. Since 1,000,000 can be written as: 10^6, and we are excluding one number (7 in this case), then we only have 9^6 numbers left. The difference:
10^6 - 9^6 =1,000,000 - 531,441 =468,559 must be "sevens".