Some numbers that you can get when you reverse the digits and they are still prime numbers are:
403 ÷ 13 = 31
2,701 ÷ 37 = 73
1,207 ÷ 17 = 71
You are 45. Remember, if a number is divisible by 5, then it must either end in 0 or 5. Therefore, since your digits are one apart, your only possibilities are 10, 45, and 65. Now, if a number is divisible by 3, the digits of that number add up to a number that is divisible by three. Of your three possibilities, this only works with 45 since 4 + 5 = 9 and 9 is divisible by 3. Hence, you are 45.
Since all of its digits are under 5, that number doesn't round up. You can round it wherever you want. 2, 2.1 and 2.13 are some possibilities.
-- The first and last digits can be 1-3, 2-4, ... 6-8, 7-9. Seven (7) possibilities. -- Or, they can be 9-7, 8-6 ... 3-1, 2-0. Eight (8) possibilities. -- Fifteen (15) possible sets of first and last digits. -- For each of those, the middle two digits can be anything from 00 to 99 ... 100 possibilities. -- Total number of 4-digit numbers that meet these specs = 15 x 100 = 1,500 .
Integers of 6 digits are normally greater than integers of 5 digits
The number 11 is prime and has two identical digits.
63
whats the answer please??
34.
You write the number and then follow it with the digits in reverse order.
For a 3 digit number, the left most or the most significant digit cannot be zero. So it can be 1,2,3,4,5,6,7,8 or 9 which is 9 possibilities. The middle number can be 0,1,2,3,4,5,6,7,8,9 which is 10 possibilties but one of the digits has been chosen already as the first digit, so the possibilities are only 9. The right most number can be 0,1,2,3,4,5,6,7,8,9 which is 10 possibilities but two of the digits have been already used by the left most and the middle digits. That leaves only 8 possibilities. So the total number of three digit numbers that have three distinct digits is 9 x 9 x 8 = 81 x 8 = 648 possibilities
38
you just carry the first number and add 5 to the second number
625. Here's how:There are five odd digits {1,3,5,7,9} so our numbers will be made using only these digits. This is the same number of possibilities as if you had a base 5 number system where the allowed digits are {0,1,2,3,4}. For a 1 digit base-5, there are 5 possibilities, for a two digit base-5 there are 5² = 25 possibilities, so for a 4-digit, there are 5^4 = 625possible. This is the same number you will have with only using odd digits.
1-digit number: 5 possibilities 2-digits number: 5 x 5 = 25 possibilities So there are 30 numbers.
If the digits can repeat, then there are 256 possible combinations. If they can't repeat, then there are 24 possibilities.
Your answer is, depending on the order of your subtraction, either positive or negative 198
The number is 21978. 21978 when multiplied by 4 which gives the result 87912 which is in reverse order.