Factors & Multiples

Factors and multiples can feel like one of those topics that’s either too easy or suddenly too hard, with not much in between. That’s actually what makes a structured program worth having. This nine-week worksheet set gives your 4th grader a steady path through the full Common Core standard (4.OA.B.4), starting with the basics and building all the way up to prime factorization and multi-step problem solving.

The first week lays the groundwork — what are factors, what are multiples, and how do they connect to multiplication and division your kid already knows? Nothing fancy, just making sure the vocabulary and core concepts are solid before things ramp up. Week 2 gets specific with factor pairs, teaching kids to systematically find every pair for a given number instead of just guessing a few. They’ll use arrays and organized tables, which honestly is a skill a lot of adults could use too.

Multiples patterns come in during Week 3. Skip counting, finding common multiples, applying it all to grouping and scheduling situations. This is where multiplication tables start feeling less like something to memorize and more like something that actually does something useful.

Then Week 4 hits prime and composite numbers. Your child will learn to classify numbers by checking their factors, and they’ll work through the Sieve of Eratosthenes to find every prime up to 100. It sounds intimidating but the worksheets break it into manageable steps, and most kids find the sieve activity genuinely satisfying.

Weeks 5 and 6 tackle GCF and LCM — greatest common factor and least common multiple. These build directly on what came before. If your child can list factor pairs and identify multiples, finding the greatest one two numbers share (or the smallest multiple they have in common) is a natural next step. The worksheets tie both concepts to practical scenarios like splitting things into equal groups or figuring out overlapping schedules.

Week 7 is where it gets interesting. Every problem is a word problem, and the challenge isn’t just doing the math — it’s figuring out which strategy to use. Should you find factors? Multiples? GCF or LCM? That decision-making practice is something a lot of worksheet packs skip entirely.

Week 8 introduces factor trees and prime factorization. Kids break composite numbers down to their prime building blocks, learn the notation, and discover that prime factorization is actually a shortcut for finding GCF and LCM. It connects everything from the previous weeks in a way that feels satisfying rather than overwhelming.

The final week is a cumulative review that mixes all nine weeks of skills together. No more “I know what to do because we just learned it” — your child has to read each problem, decide on an approach, and execute. It’s a solid way to see what’s stuck and where a quick review might help before moving on.

All worksheets come with full answer keys and are aligned to Common Core standard 4.OA.B.4.