2, 3, 5, and 7 are prime numbers for one digit numbers. 1 is NOT a prime number.
Prime numbers are pure numbers, without units or dimensions.
All of them??? There are probably infinitely many. Here are the first few numbers with 1 in the units place: 1: Not usually considered a prime number. 11: Prime 21: Not prime (divisible by 3) 31: Prime 41: Prime 51: Divisible by 3 61: Prime 71: Prime 81: Divisible by 3 91: Divisible by 7 101: Prime ...
The question doesn't apply to mixed numbers, like 2.9. A mixed number is neither one. Also, "2.9 centimeters" is not a number; it's a length. Prime and composite numbers have no units. They're just bare numbers. 29 is a prime number.
There are 5 of them.
0 Look at the product of the first 3 prime numbers: 2 x 3 x 5 = 30. Any number multiplied by 30 will have a 0 in the units digit. So, no matter how many prime numbers you are multiplying, if once you have a number ending in 0, all of the rest will end in 0.
For any integer greater than 5, where the units digit is 5 then that number can be expressed as the product of n and 5. As such, the number is composite. Therefore all numbers in the range 150 to 200 that have a units digit of 5 are composite,.
Long way: find the smallest prime numbers and use a calculator. Short way: recognize that 2 and 5 are both prime. Multiply them to get 10. We know that every multiple of ten has a 0 in the units place, so the answer to your question is 0.
17, 37, 47, 67, 97
19 29 59 79 89 Five of them.
For the tens digit to be a prime number then it must equal 2, 3, 5 or 7. There are four 3-digit prime numbers that fit the above condition and also have the tens and units digits forming a 2-digit prime number. 131, 137, 173, 179. The person supplying the question may like to sum the various combinations.