4.OA.4: Factors, Multiples, Prime and Composite
Also written as 4.OA.B.4 and CCSS.MATH.CONTENT.4.OA.B.4 · Cluster: Gain familiarity with factors and multiples.
The Official Wording
Find all factor pairs for a whole number in the range 1-100. Recognize that a whole number is a multiple of each of its factors. Determine whether a given whole number in the range 1-100 is a multiple of a given one-digit number. Determine whether a given whole number in the range 1-100 is prime or composite.
Common Core State Standards, Grade 4, Operations & Algebraic Thinking · Read it at the source · Checked October 14, 2026
What 4.OA.4 Means in Plain English
Fourth graders find every pair of whole numbers that multiplies to a given number up to 100. For 24 that is 1 × 24, 2 × 12, 3 × 8 and 4 × 6, so 24 is composite. 23 has only 1 × 23, so it is prime.
They read the same facts backward: 24 is a multiple of 1, 2, 3, 4, 6, 8, 12 and 24. In 5th grade multiples help find common denominators (5.NF.1), and in 6th grade students find greatest common factors and least common multiples (6.NS.4).
4.OA.4 I Can Statements
- I can find all the factor pairs of a number up to 100.
- I can tell whether a number is a multiple of a one-digit number.
- I can tell whether a number is prime or composite.
4.OA.4 Worked Example
Every factor pair of 48, found in order so none is missed, with a clear signal for when to stop.
Find all the factor pairs of 48. Is 48 prime or composite?
- Start with 1. Every number pairs 1 with itself.1 × 48
- Try 2, 3 and 4 in order. 48 is even, and 48 ÷ 3 = 16 and 48 ÷ 4 = 12 leave no remainder.2 × 24, 3 × 16, 4 × 12
- Try 5: 48 doesn’t end in 0 or 5, so no. Try 6: 6 × 8 = 48. Try 7: 7 × 6 = 42 and 7 × 7 = 49, so no.6 × 8
- The next number to try is 8, and 8 is already in a pair. The pairs have met in the middle, so stop.stop at 8
- 48 has more factor pairs than just 1 × 48, so it is composite.composite
Check it: Multiply each pair back to 48. In order the factors are 1, 2, 3, 4, 6, 8, 12, 16, 24 and 48, and 48 is a multiple of every one of them.
Common Mistakes with 4.OA.4
Stopping too early
Factor pairs of 48: 1 × 48, 2 × 24, 4 × 12, with 3 × 16 and 6 × 8 missing
Try this: Test every whole number in order, 1, 2, 3 and up, crossing out the misses, until the next number already appears in a pair.
Counting a square pair twice
The factors of 36 listed as 1, 2, 3, 4, 6, 6, 9, 12, 18, 36
Try this: Write 6 × 6 as one pair and 6 as one factor. 36 has nine factors, and only square numbers have an odd count.
Calling every odd number prime
“51 is odd, so it’s prime”
Try this: Test the small factors before deciding. 51 ÷ 3 = 17, so 51 is composite. So are the odd numbers 9, 15, 21 and 27.
Where 4.OA.4 Fits
Practice 4.OA.4
Quick Check
- List all the factor pairs of 36.
- Is 91 prime or composite?
- Is 84 a multiple of 7? Is it a multiple of 8?