# Geometry

posted by .

How many positive integers less than 10^20 have all their digits the same?

• Geometry -

9 1-digit
9 2-digits
...
9 20-digits
Looks like 180

## Similar Questions

1. ### DISCRETE MATH

HOW MANY POSITIVE INTEGERS LESS THAN 1000 A.are divisible by exactly one of 7 and 11?
2. ### discrete math

Find how many positive integers with exactly four decimal digits, that is, positive integers between 1000 and 9999 inclusive, have the following properties: (a) are divisible by 5 and by 7. (b) have distinct digits. (c) are not divisible …
3. ### math

How many positive integers less than 1020 have all their digits the same?
4. ### math

Find the sum of all positive integers m such that 2^m can be expressed as sums of four factorials (of positive integers). Details and assumptions The number n!, read as n factorial, is equal to the product of all positive integers …
5. ### math

How many positive integers less than 1000000 have the sum of their digits equal to 7?
6. ### math

How many positive integers less than 1000000 have the sum of their digits equal to 7?
7. ### maths

the number of positive integers less than 40000 that can be formed using all the digits 12345 is equal to
8. ### calculus

A positive multiple of 11 is good if it does not contain any even digits in its decimal representation. (a) Find the number of good integers less than 1000. (b) Determine the largest such good integer. (c) Fix b ≥ 2 an even integer. …
9. ### Pre Calculus 30

1.How many positive three-digit integers can be made from the digits {3,4,5,6,7} if digits may be repeated?
10. ### Pre Calculus 30

1.How many positive integers five-digit integers end with the digit 0?

More Similar Questions