NC 4
th
Grade Math Unpacking - Revised June 2022
Gain familiarity with factors and multiples.
NC.4.OA.4 Find all factor pairs for whole numbers up to and including 50 to:
• Recognize that a whole number is a multiple of each of its factors.
• Determine whether a given whole number is a multiple of a given one-digit number.
• Determine if the number is prime or composite.
Checking for Understanding
This standard requires students to
demonstrate understanding of factors and
multiples of whole numbers up to and
including 50. Factor pairs include two
numbers that when multiplied result in a
particular product. Students should be
given opportunities to explore factor pairs
with concrete objects and drawings to
represent arrays.
Multiples are the result of multiplying two
whole numbers. Multiples can be related
to factors, and this relationship can be
discovered through exploration with
arrays. Students can build on their
understanding of skip counting by a given
number to determine the multiples of the
given number.
As students explore and discover
patterns, they build a conceptual
understanding of prime and composite
numbers. Prime numbers have exactly
two factors, the number one and their own
number. For example, the number 17 has
the factors of 1 and 17. Composite
numbers have more than two factors. For
example, 8 has the factors 1, 2, 4, and 8.
A common misconception is that the
number 1 is prime, when it is neither
prime nor composite. Another common
misconception is that all prime numbers
are odd numbers. This is not true, since
the number 2 has only 2 factors, 1 and 2,
and is also an even number.
Recognize that a whole number is a multiple of each of its factors
Part 1:
There are 24 chairs in the art room. What are the different ways that the chairs can be arranged into equal groups if
you want at least 2 groups and want at least 2 chairs in each group?
• How do you know that you have found every arrangement? Write division equations to show your answers.
Explain how you know that you have found every arrangement.
Part 2:
There are 48 chairs in the multi-purpose room. What are the different ways that the chairs can be arranged into
equal groups if you want at least 2 groups and want at least 2 chairs in each group?
• How do you know that you have found every arrangement? Write division equations to show your answers.
• What relationship do you notice about the size of the groups if the chairs were arranged in 4 groups in both
Part 1 and Part 2?
• What about if the chairs were arranged in 8 groups? Explain why you think this relationship exists.
Possible response:
Part 1: 2 groups of 12, 3 groups of 8, 4 groups of 6, 6 groups of 4, 12 groups of 2. I know I have found
every group because the number of groups and group sizes should be all of the factors of 24 except for the
numbers 1 and 24.
Part 2: 2 groups of 24, 3 groups of 16, 4 groups of 12, 6 groups of 8, 8 groups of 6, 12 groups of 4, 16
groups of 3, 24 groups of 2.
I noticed that in Part 2 the number of chairs in a group is double or twice as large for the same number of
groups. For example, Part 1 had 4 groups of 6 and Part 2 had 4 groups of 12.
In 8 groups we have 8 groups of 3 in Part 1 and in Part 2 we have 8 groups of 6.
A landscaping company visits the school to talk about the possible ways to tile a patio and picnic area near the
playground. The school can afford between 24 and 30 square tiles.
• For each of the proposed number of tiles (24-30), determine all of the possible dimensions of rectangles
you could make.
• The space for the patio is configured so that there cannot be any more than 10 tiles in a row. For the
proposed number of tiles (24-30), determine which numbers would work as the total number of tiles.
• Which number of tiles provides the most flexibility in terms of the possible ways that the tiles could be
arranged? Explain your reasoning.
• Look at the number 29. How many different rectangles can you make? Explain whether 29 is a prime or
composite number.