What does "no digit may be composite" mean, that all the digits have to be prime numbers?
If so, then 9 is composite, and 8 is composite, but 7 is prime, so the (trivial) answer is 777777. Any other number meeting the criteria given is smaller.
This is so glaringly obvious that I can't help thinking you meant something else. You might want to ask again, but be more specific next time.
The largest number with no repeated digits is 9,876,543,210 although it is 10 digits long, the largest 3 digit number with no repeated digits is 987
That depends a lot on how often you may repeat each digit, and what operations are allowed. If you just want to write a four-digit number, using each digit once, start by writing the largest digit on the left, then continue with the second-largest, etc.
Any time. There are no restrictions on when you may or may not divide a 3-digit number!
No, and you do not even if you reverse them.
May not be, The quotient may or may not be prime.
"Composite" means that the number has smaller factors; "prime" means that it doesn't. Look at the last digit. If the digit is 0, 2, 4, 6, or 8, the number is divisible by 2. If the last digit is 0 or 5, the number is divisible by 5. If it none of those, the number may still have additional factors; but checking for this last digit can often quickly give you an answer.
The largest number with no repeated digits is 9,876,543,210 although it is 10 digits long, the largest 3 digit number with no repeated digits is 987
789634........i'm pretty sure the answer is 477560????? i may be wrong
That depends a lot on how often you may repeat each digit, and what operations are allowed. If you just want to write a four-digit number, using each digit once, start by writing the largest digit on the left, then continue with the second-largest, etc.
Any time. There are no restrictions on when you may or may not divide a 3-digit number!
A number cannot be simultaneously prime and composite. You may be thinking of the only prime number which is even, which is 2.
No, and you do not even if you reverse them.
May not be, The quotient may or may not be prime.
A multiple is a number that may be divided by another number with no remainder. Therefore, 90 is the largest two-digit multiple of 10, because 10x9 = 90, or 90 divided by 10 =9.
Any number may be added
A 17-digit number is typically referred to as a "seventeen-digit number." In mathematics, it would be classified as a whole number or an integer with 17 digits. In computing, a 17-digit number may be represented as a data type such as a long integer or a double-precision floating-point number.
That '8' at the end reveals it to be an even number. Therefore, '2' is a factor, and the number is composite. There may be more factors, but all we need is one in order to say that it's not prime.