Number Theory
Prime Numbers
Is this sum equal to a prime number?
by
Joshua Ong
Mr. White is an approximately forty years old father with 4 sons of distinct ages. Writing his age 3 times in succession, we get a 6-digit number that is equal to the product of his age, his wife's age and his 4 sons' ages.
Give the sum of his wife's age and all 4 sons' ages.
by
Drop TheProblem
A three-digit number has first digit , second digit and third digit . where and are primes. Find .
by
Sharky Kesa
How many integers from to inclusive can be written as the product of two (not necessarily distinct) primes?
If you can find a computer science or combinatorics approach, post your solution!
by
Finn Hulse
