Prime numbers
article
Public Key Cryptography
An introduction to coding and decoding messages and the maths behind how to secretly share information.
problem
Sieve of Eratosthenes
Age
11 to 14
Challenge level
Follow this recipe for sieving numbers and see what interesting patterns emerge.
problem
Number Families
Age
11 to 14
Challenge level
How many different number families can you find?
problem
HCF Expression
Age
11 to 14
Challenge level
Find out which two distinct primes less than $7$ will give the largest highest common factor of these two expressions.
problem
Three Primes
Age
14 to 16
Challenge level
Weekly Problem 6 - 2010
Can you find three primes such that their product is exactly five times their sum? Do you think you have found all possibilities?
Can you find three primes such that their product is exactly five times their sum? Do you think you have found all possibilities?
problem
How much can we spend?
Age
11 to 14
Challenge level
A country has decided to have just two different coins, 3z and 5z
coins. Which totals can be made? Is there a largest total that
cannot be made? How do you know?
problem
Prime sequences
Age
16 to 18
Challenge level
This group tasks allows you to search for arithmetic progressions
in the prime numbers. How many of the challenges will you discover
for yourself?
problem
Little Goldbach
Age
11 to 14
Challenge level
How many of the numbers 1 to 20 are not the sum of two primes?