Mini Minds Hub · Free printable
Square Number Safe Cracker: Free Printable Worksheet for Year 5
- ForYear 5
- StageKey Stage 2
- CostFree
- FormatPrintable PDF
Square Number Safe Cracker is a free printable maths worksheet for Year 5 (ages 9 to 10). Children solve each clue to open the safe, practising square numbers, cube numbers and the notation ² and ³. It needs only a pencil, and page 2 gives the grown-up notes, help ideas, a stretch task 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 safe cracker. They work through clues to find the code, so every answer feels like a step towards opening the safe. The sheet mixes multiple choice questions, each with three answers, and numbered questions with space to write the answer. Children read powers such as 6², pick out cube numbers, work with ³ and turn a written clue into a code. They are practising maths facts, not just recalling them.
- What is 6²?
- Which of these is a cube number?
- What is 10³?
- The code is the square of 8. Write the code.
A worked example with a different number
What is 7²?
This example uses a number that is different from the ones children meet on the sheet. It shows two ways to think about a square number.
Method 1: multiply the number by itself- The small 2 means use the number twice in a multiplication.
- Write it out: 7² = 7 × 7.
- Use a known fact, or split it: 7 × 5 = 35 and 7 × 2 = 14.
- Add the parts: 35 + 14 = 49.
- Draw 7 rows with 7 dots in each row.
- Count the first 5 rows: 5 × 7 = 35 dots.
- Count the last 2 rows: 2 × 7 = 14 dots.
- Add them: 35 + 14 = 49 dots.
Ways to build confidence with squares and cubes
Picture it
Squares come from square shapes and cubes come from cube shapes. Let children draw dot squares or stack small blocks so the words have a picture behind them.
Say it aloud
Read 5² as five squared and 5³ as five cubed. Saying the words helps children link the notation to the idea.
Write it out in full
Ask children to write a power as a multiplication first, such as 4³ as 4 × 4 × 4. Then work it out one step at a time.
Spot the difference
Put a square and a cube side by side with the same base number. Talk about why the two answers are not the same.
What are square and cube numbers?
A square number is what you get when you multiply a whole number by itself. The name comes from the shape. If you arrange counters in equal rows and equal columns, they make a square. We write a square using a small raised 2, so 9² means 9 × 9. A common slip is to think squaring means doubling. It does not.
A cube number is what you get when you multiply a whole number by itself, then by the same number again. The name comes from building a cube out of small equal cubes. We write a cube with a small raised 3. So 2³ means 2 × 2 × 2. Powers are a short way to write repeated multiplication, and they appear again in later maths.
Fun facts about squares and cubes
- The small raised 2 in 5² is read as squared.
- The small raised 3 in 5³ is read as cubed.
- Square numbers get their name from the square shape that counters can make.
- Cube numbers get their name from the cube shape, which has the same length, width and height.
- A power is a short way to write a repeated multiplication.
Skills and curriculum link
- Square numbers
- Cube numbers
- Reading ² and ³
- Repeated multiplication
- Times table facts
- Explaining your thinking
Ideas that help with squares and cubes
- Count the copiesThe small raised number tells you how many copies of the base number to multiply together. Two copies for ², three copies for ³.
- Use what you knowTimes table facts do most of the work for squares. A secure fact like 4 × 6 helps children check nearby answers.
- Build it in stepsFor a cube, multiply the first two copies, then multiply that answer by the last copy. Writing each step stops mistakes.
- Check it makes senseA cube is usually much bigger than the square of the same number. If an answer looks too small, go back and check the steps.
Key words
- Square numberThe answer when you multiply a whole number by itself. For example, 5 × 5 gives a square number.
- Cube numberThe answer when you multiply a whole number by itself, then by the same number again. For example, 4 × 4 × 4 gives a cube number.
- SquaredSaid when a number has a small raised 2. 6² is read as six squared.
- CubedSaid when a number has a small raised 3. 6³ is read as six cubed.
- PowerA number written with a small raised number, such as 5². It is a short way to write a repeated multiplication.
- IndexThe small raised number in a power. It tells you how many copies of the number to multiply together.
How to use it
- Print both pages. Page 1 is for your child. Keep page 2, which has the notes and answers.
- Read the first clue together. Ask your child what the small raised number is telling them to do.
- Work through the clues in order. Your child says each answer aloud before writing it down.
- Check using page 2. Ask, "How did you work that out?" The thinking matters as much as the answer.
- Come back another day and try the clues that felt tricky again. Repeating a familiar sheet builds confidence.
Help, stretch and game ideas
If it feels too hard
Let your child draw dot squares or build small cube towers from blocks, so they can see why a power gives its answer. Write each power as a full multiplication first. Do the clues one at a time and take breaks between them.
To stretch confident children
Ask your child to list every square number up to 144. Then ask them to find which of those are also cube numbers. Can they explain why some numbers appear on both lists? Then invite them to write a safe clue of their own.
Make it a game
Play detective pairs. One child says a power, such as 5², and the other races to give the answer. Swap roles after each round. Add a point for each correct answer and a bonus point for explaining the method.
Mistakes to watch for
Watch forA child reads 5² as 5 × 2 and gets the answer wrong.
Try thisSay it as "two copies of 5" and write 5 × 5. Draw 5 rows of 5 dots to show why.
Watch forA child treats a cube as three times the number, so 10³ becomes 10 × 3.
Try thisWrite the power out as 10 × 10 × 10. Say "three copies of ten, multiplied together, not added."
Watch forA child mixes up ² and ³ and uses the wrong number of copies.
Try thisLink the number to the shape. Two is for a flat square, three is for a solid cube. Count the copies on your fingers.
Talk about it
- What does the small raised number tell you to do?
- How could you show a square number with counters or dots?
- Why do you think we call these numbers squares and cubes?
- Is squaring a number the same as doubling it? How can you tell?
- Which clue felt easiest, and what made it easy?
- How could you check an answer without using a calculator?
Take it off the page
Counter squares
Use buttons, pasta shapes or coins to build squares from equal rows and columns. Count the counters in each square and write it as a power.
Block towers
Use small cubes or building blocks to build a bigger cube. Count how many small blocks it needs and talk about the three equal edges.
Safe code hunt
Hide a short note in a box with a written power as the clue. The finder works out the code before opening the box.
Who it is for
Parents
Sit beside your child for the first clue, then let them lead. Ask them to explain each answer in their own words. If they get stuck, let them draw dots or build with blocks.
Teachers
Use it as a starter, plenary, early finisher task or homework after teaching square and cube numbers. It needs no preparation beyond printing. Page 2 has support, stretch and answers for mixed ability groups.
Home educators
Pair the sheet with practical work such as building with blocks or arranging counters. It is free to print again for brothers and sisters, or for a quick revision task a few weeks later.
Where this fits in your child's maths
Before this sheet, children learn their times tables and see multiplication as equal groups and arrays. A secure grasp of those facts makes squares much easier, because a square is a times table fact with the same number twice.
After this, children use squares and cubes in work on area and volume, and later meet powers and roots in more depth. Confidence with the notation ² and ³ now gives them a good foundation for that work.
Questions parents and teachers ask
- What age is Square Number Safe Cracker for?
It is written for Year 5 (ages 9 to 10) in Key Stage 2. Younger children who know their times tables well may enjoy it, and older children can use it as quick revision.
- What will children practise?
Children practise recognising square numbers and cube numbers, and using the notation ² and ³. They also get practice with repeated multiplication and with reading short written clues.
- How do I use the sheet?
Print both pages and give page 1 to your child. Work through the clues in order. Children should say each answer aloud before writing it down. Use page 2 to check answers together.
- What if my child finds it too hard?
Let them draw dot squares or build small cube towers so they can see why a power gives its answer. Write each power as a full multiplication first, and do just a few clues at a time.
- Is it free to use?
Yes. It is free to print for home and classroom use. You can print it again for brothers and sisters, or for revision a few weeks later.
- Can teachers use it in class?
Yes. Teachers can use it as a starter, plenary, early finisher task, homework or table activity. It needs no preparation beyond printing, and page 2 has support and stretch ideas.
- Do I need to print in colour?
No. It prints well in black and white on plain A4 paper, so it is cheap and easy to use at home or in school.
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.