Three of them: 7, 77, and 777 .
Only the multiples of 1000.
Two prime numbers, 61 and 67, are the only prime numbers between 60 and 70.
There are an infinite list of different numbers, but only 90 of them are integers (whole numbers).
1111 is the only one.
Only one . . . 101 .
Only the multiples of 1000.
The only one is 1,009.
1,3,5,7,9,11,13,15,17,19,31,33,35,37,39,51,53,55,57,59,71,73,75,77,079, 91,93,95,97,99,111,113,115,117,119,131,133,135,137,139,151,153,155, 157,159,171,173,175,177,179,191,193,195,197,199,311,313,315,317,319, 331,333,335,337,339,351,353,355,357,359,371,373,375,377,379,391,393, 395,397,399,511,513,515,517,519,531,533,535,537,539,551,553,555,557, 0559,571,573,575,579,591,593,595,597,599,711,713,715,717,719,731,733, 735,737,739,751,753,755,757,759,771,773,775,777,779,791,793,795,797, 799,911,913,915,917,919,931,933,935,937,939,951,953,955,957,959,971, 973,975,977,979,991,993,995,997,999
There are infinitely many numbers between any two numbers. But there are only 9 integers between them.
How many
every number is unique and equal only to itself. The only number that is equal to 1000 is 1000.
The numbers 23 and 29 are the only prime numbers between 20 and 30
Two prime numbers, 61 and 67, are the only prime numbers between 60 and 70.
There are an infinite list of different numbers, but only 90 of them are integers (whole numbers).
1024, 2048, 4096 and 8192
2, 4, 8, 16, 32, 64, 128, 256, and 512
The only integer with this property is 31. There are infinitely and uncountably many such non-integral numbers, within the open interval between 30 and 31.6.