Factors, multiples and primes
Factors as rectangles, prime numbers on a number grid and multiples as times tables. Read one step, play with it, then tap “I understand this”.
Factors: numbers that divide exactly
A factor of 12 is a number that divides into 12 with no remainder: 1, 2, 3, 4, 6 and 12. Factors come in pairs: 3 × 4 = 12, so 3 and 4 are both factors.
Factor rectangles
Choose a number. Every rectangle you can build with all the blocks is a factor pair.
Find factors in pairs: start with 1 × 12, then 2 × 6, then 3 × 4. When the pairs turn around (4 × 3), you have them all.
If 3 divides into 12, there is another number that tells you how many times: 12 ÷ 3 = 4. So you always get two factors together, 3 and 4. Only for a square number like 16 are the two the same (4 × 4).
Prime and composite numbers
A prime number has exactly two factors: 1 and itself (2, 3, 5, 7, 11 …). A composite number has more than two. 1 is neither.
The number grid
Show the primes or the multiples of a number. Tap a number for its factors.
2 is the only even prime. Every other even number divides by 2.
A prime number has exactly two different factors: 1 and itself. 1 has only one factor (1 itself). That is why 1 is not prime, and not composite either.
Multiples
Multiples of 3 are the 3 times table: 3, 6, 9, 12, 15 … They go on and on. Use the number grid in step 2 and choose “Show multiples” to see them.
Factors are smaller than or equal to the number (there are only a few). Multiples are bigger than or equal to the number (they never stop).
4 is a factor of 12, and 12 is a multiple of 4. Do not swap the two words.
Prime or not?
Prime or composite?
Choose for each number.
Correct: 0Check yourself
- A factor divides exactly into a number; factors come in pairs (3 × 4 = 12).
- Prime: exactly 2 factors. 1 is not prime; 2 is the only even prime.
- Multiples are the times table: they are bigger than or equal to the number.
Write these points in your maths book. Read them again the night before the test.
Quick questions
Tap an answer. If you get one wrong, read why and go back to that step. You get new questions every time.
You ticked all 4 steps! Now you are ready for the quiz.- Practice sheet for this classQuestions + memo · 2 A4 pagesPractice sheet
- Numbers16 pages · PDFPaperMemo
Ready for more? The Grade 5 factors quiz gives you new questions every time.
- One step a day is enough. Ten calm minutes work better than an hour the night before the test.
- Ask at the dinner table: “Can 24 sweets be shared equally between 5 children? And 6?” That is factors.
- Ask your child to tell you the rule in their own words. If they can explain it, they understand it.
- The ticks (“I understand this”) are saved on this device only. We never ask for names or emails.
Follows CAPS for Grade 5 Maths. Always check your teacher’s notes and textbook too.