A sorting activity for Year 5 maths built around a jammed number-sorting machine. Pupils place 16 numbers into four columns: primes, squares, cubes and other composites. Reasoning questions follow, including why 64 cannot sit in just one column and whether all prime numbers are odd. Explained answers are included. It covers England National Curriculum objectives on primes, squares and cubes.
Number - multiplication and division
“Know and use the vocabulary of prime numbers, prime factors and composite (non-prime) numbers”
The four column headings force pupils to use this vocabulary correctly.
Number - multiplication and division
“Establish whether a number up to 100 is prime and recall prime numbers up to 19”
Sorting the 16 numbers requires testing each for primality.
Number - multiplication and division
“Recognise and use square numbers and cube numbers, and the notation for squared (²) and cubed (³)”
The 64 question shows a number can be both square and cube.
A short scenario: the sorting machine has jammed and 16 numbers need placing by hand.
Pupils sort the numbers into Prime, Square, Cube and Other Composite columns.
Questions on the hardest number to place, a true-or-false on odd primes, and why 64 fits two columns.
Full solutions with explanations for all four reasoning questions.
Paired task
Sort the numbers in pairs, then debate the 64 question as a class.
Assessment check
The true-or-false on odd primes catches the common belief that 2 is not prime.
Early finishers
Adding a new number to each category extends the task naturally.
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