Year 5 Factors & Multiples Detective Pack
Year 5 factors, multiples and prime numbers maths investigation pack with engaging detective games, reasoning challenges and greater-depth activities.
Turn factors and multiples into a full mathematical investigation with this Factor Detective Year 5 Maths Pack.
Designed for the Year 5 UK National Curriculum, this detective-themed resource develops fluency, reasoning and problem-solving skills while exploring factors, multiples, factor pairs, prime numbers, composite numbers and number properties.
Rather than relying on repetitive worksheets, pupils become mathematical detectives: solving mystery numbers, eliminating suspects, testing evidence, identifying false statements and proving their conclusions.
The pack includes:
18 Factor Detective Case Files across three challenge levels: Detective, Senior Detective and Chief Inspector
6 Open Investigations where pupils must identify a lying witness and solve the mystery number
Evidence Board with 6 clue trails for use with a 1–100 square – ideal for whole-class or paired reasoning
Evidence Check with 10 true-or-false statements requiring pupils to justify their answers with mathematical evidence
Prime Suspects Investigation using systematic elimination on a 1–100 square to discover prime and composite numbers
6 Prime Evidence Files providing deeper reasoning and problem-solving challenges
Pupil recording resources
Worked answers
Detailed Teacher Guide explaining how to organise, teach, differentiate and extend each activity
Maths skills covered
The activities give pupils opportunities to:
identify multiples and factors
find and use factor pairs
reason about factors and multiples
recognise and investigate prime and composite numbers
identify prime numbers below 100
use mathematical vocabulary accurately
eliminate possibilities systematically
explain mathematical reasoning
find examples and counterexamples
spot misconceptions and incorrect reasoning
justify and prove answers
tackle greater-depth reasoning and problem solving
Flexible classroom use
The resources can be used for whole-class teaching, independent work, paired investigations, maths centres, interventions, early-finisher challenges, revision or assessment.
The three levels of Factor Detective cards make differentiation straightforward, while the more open-ended investigations and Prime Evidence Files provide opportunities to challenge pupils working at greater depth.
Many of the resources are designed to be low-ink and reusable, making them suitable for printing, laminating and using with multiple classes.
A fun alternative to a traditional factors and multiples worksheet, with plenty of mathematical substance behind the detective theme.
Suitable for Year 5 / Upper KS2.




