Factors, multiples and primes
Grade 4 · Level 4 · Sheet 1the answers
Circle the answer.
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- 1.
Is this number prime or composite?
77primecomposite - 2.
Is this number prime or composite?
13primecomposite - 3.
Is this number prime or composite?
69compositeprime - 4.
Is this number prime or composite?
31primecomposite - 5.
Is this number prime or composite?
43compositeprime - 6.
Is this number prime or composite?
15primecomposite - 7.
Is this number prime or composite?
39primecomposite - 8.
Is this number prime or composite?
25primecomposite - 9.
Is this number prime or composite?
19compositeprime - 10.
Is this number prime or composite?
11compositeprime - 11.
Is this number prime or composite?
51primecomposite - 12.
Is this number prime or composite?
49compositeprime
Show the answer key
- 1.composite
- 2.prime
- 3.composite
- 4.prime
- 5.prime
- 6.composite
- 7.composite
- 8.composite
- 9.prime
- 10.prime
- 11.composite
- 12.composite
Answer key · Factors, multiples and primes · Level 4 · Sheet 1
- 1.composite
- 2.prime
- 3.composite
- 4.prime
- 5.prime
- 6.composite
- 7.composite
- 8.composite
- 9.prime
- 10.prime
- 11.composite
- 12.composite
The mistakes behind most wrong answers
A wrong answer in factors, multiples and primes is rarely random. These are the ones that come up most often, each on a real problem — worth knowing before you mark a sheet, because the fix for each is different.
Is this number prime or composite?
91The answer is composite. A child who answers prime probably missed a factor that was there.
Is this number prime or composite?
19The answer is prime. A child who answers composite probably assumed the number had to come apart.
How many factor pairs does this number have?
100The answer is 5. A child who answers 9 probably counted the factors instead of the pairs.
How many factor pairs does this number have?
45The answer is 3. A child who answers 2 probably left out one and the number itself.
In the app, every wrong answer is matched against mistakes like these, and the weekly email tells you which one your child keeps making — in those words, not as a percentage.