Mini Minds Hub · Free printable

Maths Detective Cases: Free Printable Game for Year 4

  • ForYear 4
  • StageKey Stage 2
  • CostFree
  • FormatPrintable PDF
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Maths Detective Cases is a free printable game for Year 4 (ages 8 to 9). There are two cases to crack. In each one, children use number clues to rule suspects out until only the culprit is left. It takes about 15 minutes, needs only a pencil, and page 2 gives the grown-up notes, help ideas, a stretch idea and the answers.

It comes from the Mini Minds Hub, the free library of printables from Jaques of London, the British games and toy company that has been making games for families since 1795. Print both pages, give page 1 to your child and keep page 2 for yourself. Black and white printing works well.

What is on the sheet

Children play detective. Each case has a line of suspects and a set of number clues. A clue might point to a times table, say whether a number is odd, compare it with a target, or talk about its digits. After each clue, children decide who is out and who is left. At the end of each case they write the name of the culprit.

  • Case 1, clue 1: the number is in the 4 times table. Who is out?
  • Case 1, clue 2: the number is more than 40. Who is out?
  • Case 1, clue 3: the digits add up to 12. Who is left?
  • Case 1: the culprit is ...
  • Case 2, clue 1: the number is in the 9 times table. Who is out?
  • Case 2, clue 2: the number is odd. Who is out?
  • Case 2, clue 3: the number is less than 50. Who is left?
  • Case 2: the culprit is ...

A different case to try first

Five suspects wear the numbers 18, 21, 35, 49 and 64. Clue 1: the number is in the 7 times table. Clue 2: the number is more than 30. Clue 3: the digits add up to 13. Who is the culprit?

This is a made up case for practice. It uses different numbers and clues from the sheet. It shows two ways to work.

Method 1: cross out as you go
  1. Write the five numbers in a row.
  2. Clue 1: the 7 times table includes 21, 35 and 49. Cross out 18 and 64.
  3. Clue 2: more than 30. Cross out 21, because it is less than 30.
  4. Clue 3: digits add up to 13. For 35, 3 + 5 = 8, so cross it out. For 49, 4 + 9 = 13, so it stays.
Method 2: test one suspect at a time
  1. Take 18. It is not in the 7 times table, so it is out.
  2. Take 21. It fails clue 2, so it is out.
  3. Take 35. It passes clues 1 and 2 but fails clue 3, so it is out.
  4. Take 64. It is not in the 7 times table, so it is out. Take 49. It passes all three clues.
The culprit is 49.

Why number clues build reasoning

Detective puzzles like this use a skill called elimination. Each clue removes some suspects, and the list gets shorter until one is left. Children cannot guess their way through. They must read a clue carefully, test every suspect against it and decide. That is logical reasoning, and it is a useful habit in maths and in everyday life.

Times tables work as the tests inside the clues. Children ask whether a number belongs to a table, so quick recall helps them focus on the logic. In Year 4, children work towards knowing their multiplication tables up to 12 times 12. The other clues touch odd and even numbers, comparing numbers and adding digits, which all link to place value.

Skills and curriculum link

  • Times tables
  • Logical reasoning
  • Odd and even numbers
  • Comparing numbers
  • Adding digits
  • Checking answers

Ways to help your detective

  • Read each clue twiceAsk your child to read the clue aloud, then say it again in their own words. Clear understanding of the clue comes before any crossing out.
  • Test every suspectEncourage them to check each number against the clue, one at a time. Skipping a suspect is the easiest way to miss something.
  • Say the table out loudIf a clue names a times table, chant it quietly or write the first few multiples at the side of the page. Then check each suspect against the list.
  • Check the culprit at the endOnce one suspect is left, read all the clues again for that case. The culprit must fit every one.

Key words

  • ClueA piece of information that helps you work something out.
  • SuspectOne of the people who might be the culprit.
  • Rule outDecide that something cannot be right and cross it off.
  • MultipleA number you find in a times table. 14 is a multiple of 7.
  • DigitOne of the symbols 0 to 9 used to write numbers. The number 52 has the digits 5 and 2.
  • Odd numberA whole number that cannot be shared into two equal groups. It ends in 1, 3, 5, 7 or 9.

How to use it

  1. Print both pages. Page 1 is for your child. Keep page 2, which has the notes and answers.
  2. Read the rules and the first clue aloud together. Ask your child to say what the clue is asking in their own words.
  3. Work through Case 1 together the first time. Talk about each choice and why a suspect is in or out.
  4. Let your child lead Case 2. Check both culprits against the answers on page 2, and ask how they decided.
  5. Come back to it another day. Try 2 players racing, or time yourselves and try to beat your best.

Help, stretch and game ideas

If it feels too hard

Cross out each suspect on the page as a clue rules them out. Do one clue at a time. If a times table clue is tricky, write out the first few multiples of that number at the side of the page and check each suspect against them.

To stretch confident children

Write a third case with five suspects and three clues for a friend to solve. Choose the culprit first, then write clues that point to them. Check that your clues leave only one suspect before you hand the case over.

Make it a game

Play with 2 players racing. Both solve the same case, and the first to name the right culprit wins the round. Or play alone and time yourself, then try to beat your best on another day.

Talk about it

  • Which clue did you find easiest to use, and why?
  • How did you know a number was in the times table?
  • Did any clue rule out more than one suspect? How did you spot that?
  • What would happen if we swapped the order of the clues? Would we still find the culprit?
  • How can you be sure your culprit is right? Which clues did you check?
  • What clue would you write to make a case harder?

Take it off the page

Suspect cards

Write numbers on small pieces of paper and lay them out face up. Make up a clue, such as a times table or odd and even, and take turns removing the cards that do not fit.

Guess my number

One person thinks of a number and gives clues one at a time. The other person writes down what is still possible after each clue, until only one number is left.

Times table walk

Choose a times table and say a multiple on each step you take around the garden or the house. Then make up a clue about one of the numbers you said.

Who it is for

Parents

Sit with your child for the first case, then let them lead the second. Keep it to about 15 minutes. If they get stuck, ask them to cross out suspects one clue at a time.

Teachers

Use it as a starter, plenary, early finisher task or supply resource. It needs no preparation beyond printing. Page 2 gives support and stretch ideas for mixed ability groups, so pairs can work at different levels.

Home educators

Pair it with everyday number talk, such as spotting multiples on a walk or in a shop. Print it again for brothers and sisters, or use it for revision of times tables a few weeks later.

Where this fits in maths

Before this, children learn to count in steps and to recall the 2, 5 and 10 times tables, then the 3, 4 and 8. They also meet odd and even numbers and compare numbers using more than and less than.

After this, children in Year 5 and Year 6 work with multiples and factors, and learn about prime numbers. The reasoning habit of testing every possibility against a rule carries into those topics and into later problem solving.

Questions parents and teachers ask

What age is Maths Detective Cases for?

It is written for Year 4 (ages 8 to 9), in Key Stage 2. Younger children can try it with a grown-up. Older children can use it as quick times table practice or write their own cases.

How long does it take?

It takes about 15 minutes. Children who like to talk through each clue may take a little longer. You can do one case now and save the second for another day.

Do I need the answers?

Yes, they are useful. Page 2 is for the grown-up and has the answers, notes on how to use the sheet, help for children who find it hard and a stretch idea.

What if my child finds it hard?

Let them cross out each suspect on the page as a clue rules them out. Work on one clue at a time. For a times table clue, write out the first few multiples at the side.

Can two children play together?

Yes. It works for 1 player, or 2 players racing. Both solve the same case and the first to name the right culprit wins the round. Take turns reading the clues aloud.

Do I need to print in colour?

No. It prints well in black and white on plain A4 paper. You only need a pencil, and an eraser helps if a child changes their mind about a suspect.

Can teachers use it in class?

Yes. It works as a starter, plenary, early finisher task, homework or table activity. It needs no preparation beyond printing, and it is free to print for classroom use.

Preview the full PDF

Made by Jaques of London, making games for families since 1795. A printable supports classroom learning and does not replace a teacher.

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