Hi,

How many two-digit counting numbers are not a multiple of 10?

Cannot use 0 in the tens place and not using 0 in the ones place...

 

Or

   two-digit counting numbers minus 9 multiple of tens = 81  

RELATED QUESTIONS

How many two digit counting numbers are not a multiple of 20! I dont know how to get the... (answered by Boreal,MathTherapy)

How many 3-digit numbers are multiple of 21?
I can solve it by counting there is another  (answered by robertb,ikleyn,Edwin McCravy)

How many 3 digit counting numbers are... (answered by fractalier,AnlytcPhil)

 How many positive two-digit integers are multiple of... (answered by KMST)

Principles of Counting or Permutations.  What formula do I use here.

Telephone... (answered by palanisamy)

The counting numbers beginning with 101 and ending with 200 are listed. How many of the... (answered by Boreal)

How many three-digit counting numbers do not contain any of the digits 1, 5, 7, 8, or... (answered by stanbon)

a) How many seven-digit telephone numbers have one digit which is a multiple of 4 and six  (answered by ikleyn)

How many three-digit counting numbers less than 500 have digits that are all... (answered by Boreal,ikleyn)