How to Find All the Factors of Any Number? A Kid-Friendly Guide with Methods & Examples
Mathnasium tutors walk you through finding factors with three step-by-step methods, solved examples, practice problems, and common FAQs.
With calculators, smartphones, and more recently, AI tools close at hand, students have more ways than ever to get quick answers in math.
But that convenience comes with a cost.
Relying heavily on external tools for calculations takes a toll on a student’s own cognitive superpower: mental math.
At Mathnasium, mental math is one of the core strategies we use to help students make sense of math, not just get through it. And when we focus on it, the results reach far beyond faster calculations, boosting skills students carry into both academic work and everyday life.
With that in mind, our tutors have put together a breakdown of what mental math really is, plus five key reasons it supports long-term success in math and beyond.
Mental math is the ability to work through math problems in your head, using reasoning and number sense instead of tools like calculators or paper.
What some people get confused about is thinking it’s the same as memorizing answers, like how you memorize times tables. But mental math is something different.
It’s where you use strategies like rounding numbers, breaking apart values, or spotting patterns to simplify calculations.
What does that look like in practice?
To calculate 7 × 13 mentally, a student might split the 13 into 10 and 3. They solve:
7 × 10 = 70
7 × 3 = 21
Then combine: 70 + 21 = 91
Instead of following a fixed algorithm, they break the problem into parts that feel manageable and solve it in their head.
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Just like reading fluency or musical ability, mental math is a skill that takes training. And when it’s developed with intention, the benefits reach beyond a child’s math journey into how they think, solve problems, and approach challenges in everyday life.
In mental math, a number like 48 becomes 50 minus 2, or 6 times 8, or nearly 10 less than 58. With that kind of flexibility, math stops feeling like a set of rules and starts becoming something students can shape and understand.
At Mathnasium, this is often where progress begins. Once students learn how to shift numbers in their head, to round, regroup, or break them apart, they start thinking more clearly about what a problem is really asking.
A study published in the Journal of Mathematics Education links mental math proficiency with a stronger grasp of number relationships and arithmetic operations, which are essential components of number sense.
The takeaway?
When number sense clicks, everything built on top of it gets sturdier and less stressful.
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Estimation is a core math skill that sharpens a student’s ability to reason with numbers.
The more a child practices mental math, the more efficient they become at making quick, reasonable estimates.
Picture a student solving 198 + 347. Rather than lining up digits right away, they round to 200 + 350, get 550 in a flash, then adjust if needed.
Each approximation builds toward a stronger internal sense of what makes numerical sense.
And that sense doesn’t stay confined to math problems.
Students who grow confident in estimation tend to apply it naturally. They might gauge how much time is left in a class period before starting an assignment, or quickly assess whether a $20 bill will cover what’s in their cart.
Estimation supports sound, in-the-moment decisions that don’t require a calculator.

Mental math builds estimation skills students can use in math and real life.
In a recent study with middle and high school students, those who practiced mental calculations daily for just 12 days showed measurable improvement in problem-solving skills.
Gains on pre- and post-tests revealed that mental math practice supports how students reason through problems, not just how quickly they compute.
We see this in our centers all the time.
Say a student gets a word problem that reads: A jacket originally costs $48. It’s on sale for 25% off. If you have $40, do you have enough to buy it, including tax?
They know 50% of $48 is $24. Half of that is $12, so 25% off means subtracting $12. That brings the price down to $36. With a little room for tax, they’re likely still under budget.
Instead of reaching for a calculator, a student reasons through the math.
With more moments like this, that habit can reshape how they approach not just math problems, but real-life decisions too.
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Mental math takes focus.
Students have to hold numbers in their heads and stay mentally organized, all without distractions.
That kind of attention builds over time.
Educational research shows that regular mental calculation helps train the brain’s executive functions, especially attention control.
And when focus improves, learning gets easier across the board.

Mental math helps students build focus by holding numbers and steps in their heads while solving.
Every time a student solves something in their head, they’re proving to themselves that they can. That sense of control builds confidence.
As mental math gets easier, motivation goes up. Students take more risks and stick with problems longer because they believe they’re capable.
At Mathnasium, we’ve seen this shift in students who once felt anxious about math. Mental strategies give them a way in, and with each success, that hesitation begins to fade.
Research supports this too: studies show that mental math practice improves students’ self-efficacy and leads to a more positive, persistent approach to problem-solving.
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When students turn to Mathnasium for support, they don’t receive a one-size-fits-all program. Our proprietary teaching approach, the Mathnasium Method™, is designed to meet each student where they are, because we know that no two learners think the same way.
It all starts with a diagnostic assessment. Beyond just a skill check, this is a window into what a student understands, where they need support, and how they learn best.
With insights from the assessment, we build a personalized learning plan tailored to each student’s needs. No two plans are exactly alike. Each one targets knowledge gaps, reinforces strengths, and guides instruction step by step.
Once that plan is in place, our tutors bring it to life through face-to-face instruction in an environment that’s both engaging and confidence-building. We use a combination of verbal, visual, tactile, written, and mental strategies because students learn best when they experience math from multiple angles.
Mental math is an important factor in that process. During sessions, students learn to break down problems, explore patterns, and make sense of numbers without relying on calculators or rigid steps. They also get time to work through challenges independently, which strengthens problem-solving and critical thinking along the way.
Over time, students don’t just improve their skills but also change how they think and feel about math. The transformation is measurable:
94% of parents report an improvement in their child’s math skills and understanding.
93% of parents report an improved attitude toward math after attending Mathnasium.
90% of students saw an improvement in their school grades

Parents trust Mathnasium because they see real progress, open communication, and a team that understands how their child learns best.
Whether your child needs to catch up, keep up, or get ahead, Mathnasium offers a personalized path toward lasting success, with mental math as a core part of the journey.
Reach out to your local center to schedule a diagnostic assessment and take the first step toward long-term math success.
Mathnasium of Denver Highland is a math-only learning center for K-12 students in Denver, CO. Trusted by over a million parents, Mathnasium uses personalized learning plans and the proprietary Mathnasium Method™ to help students catch up, keep up, and get ahead on their math journey.
Our specially trained tutors deliver face-to-face instruction in a supportive and fun small-group environment, working with students both in center and online to develop a deep understanding of math, build confidence, and improve academic performance.
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