3 13 23 43 53 73 83 103 113 163 173 193
Yes
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,.
There is no simple formula for that; I suggest you look up the prime numbers in a table of prime numbers, analyzing each prime number in the range 10-99 whether it fulfills this specific criterion.
In every 100 there are 10 numbers that have a units digit of 2 and 10 with 7, making 2 with 2 or 7. Between 0 and 1000 there are 10 hundreds, making 10 × 20 = 200 such numbers. BUT 2 and 7 are less than 10, so there are two less such numbers, making 200 - 2 = 198 such numbers.
Oh, what a lovely question! If we're looking for 2-digit numbers where the one's digit is greater than the ten's digit, we simply need to think about the possibilities. There are 36 such numbers, ranging from 12 to 98. Just imagine all the happy little numbers waiting to be discovered!
There are 5 of them.
17, 37, 47, 67, 97
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.
2, 3, 5, and 7 are prime numbers for one digit numbers. 1 is NOT a prime number.
Yes
The prime numbers with a units digit of 1 in the range 1 - 121 are :- 11, 31, 41, 61, 71 and 101.......making 6 primes in total.
90 of them.
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,.
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.
There is no simple formula for that; I suggest you look up the prime numbers in a table of prime numbers, analyzing each prime number in the range 10-99 whether it fulfills this specific criterion.
19 29 59 79 89 Five of them.
The last digit in the product of the first 20 odd natural numbers can be determined by looking at the pattern of the units digit in the multiplication of consecutive odd numbers. The units digit of the product of consecutive odd numbers alternates between 1 and 5. Since there are 10 odd numbers between 1 and 19, and 20 is also an odd number, the last digit in the product of the first 20 odd natural numbers is 5.