44 for example should be written forty four.
There is no such ratio that applies for all single-digit and double-digit integers.
There are 45 such numbers.
no
Yes.
you say one number first then the other one for example 789 you say seven eight and then nine
there are 50 prime numbers between 1-100 and of them 2,3,5,7 are single digit so that would leave 46 double digit prime numbers between 1-100
When the units digit equals the tens digit then the sum of the digits of a 2 digit number is double the units digit. In each tens range above 50, numbers below this critical point meet the requirement, numbers above this critical point have a sum LESS than double the units digit. The applicable numbers are 51-54 (4), 61-65 (5), 71-76 (6), 81-87 (7) and 91-98 (8). Then there are 4 + 5 + 6 + 7 + 8 = 30 qualifying numbers.
3 digit numbers are lessthan 4 digit numbers
124
The answer will depend on how many digits there are in each of the 30 numbers. If the 30 numbers are all 6-digit numbers then the answer is NONE! If the 30 numbers are the first 30 counting numbers then there are 126 combinations of five 1-digit numbers, 1764 combinations of three 1-digit numbers and one 2-digit number, and 1710 combinations of one 1-digit number and two 2-digit numbers. That makes a total of 3600 5-digit combinations.
There are 6.They are:15,45,75,51,54,57.If you want to include negative numbers (i.e. -15 etc...) then you can double the answer.
A 3 or 4 digit number.