Author: Bon Crowder

  • The Best Online Math Dictionary for Kids

    The Best Online Math Dictionary for Kids

    UPDATE June 2026: This tool is still available, however it’s no longer interactive Unless you use the version captured on the Wayback Machine. I’ve included links for both the current static version as well as the Wayback Machine’s interactive version in the post.

    My friend and fellow educator, Jeri, shared with me a super find — A Maths Dictionary for Kids by Jenny Eather (static, interactive).

    I have a lot of math dictionaries, and have seen many online. Generally they all do the same thing — give definitions.

    But the interactive version of A Maths Dictionary for Kids does something more than all the others — it gives kids a chance to experience the words.

    After playing around with it a bit, I’ve decided that it’s the best online math dictionary I’ve ever seen — even better than Wolfram’s MathWorld!

    It’s not just for kids!

    Yes, it’s colorful, interactive and easy to use. But that doesn’t mean you have to be a little one to appreciate it.

    As a grownup you’ll also enjoy the interactive version of A Maths Dictionary for Kids. Head over there now and pick some terms to play with. Here are some good ones to start with:

    • Absolute value
    • Attribute (shown in the video)
    • Centre of rotation
    • MPH
    • Terminating decimal
    • Three-dimentional
    • y-coordinate

    Print it out and use it!

    If you do something cool you can print it out and use it as a handout.

    On the left is what you see on the site, on the right is the printout!

    UPDATE June 2026: The print function doesn’t work in the interactive version from the Wayback Machine. However, you can still do a screenshot.

    What do you think? Can you use it?

    Share your thoughts in the comments or on twitter/x.

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  • 8 Digit Puzzle — Rules, Downloadable and Questions to Ponder

    8 Digit Puzzle — Rules, Downloadable and Questions to Ponder

    A friend of mine is putting together an amazing class on using mathematics as meditation.

    One of the tools she’ll be using is the 8 Digit Puzzle.

    The 8 Digit Puzzle

    To play, download or draw out the puzzle board on a piece of paper.

    Then cut out the numbers 1-8 from slips of paper. Make sure your numbers will fit in your puzzle board’s boxes.

    You can download the 8 Digit Puzzle Board & Numbers here (it also has some fun questions to ponder).

    The board looks like this:

    Place the numbers in the puzzle so that no two consecutive numbers are next to each other horizontally, vertically, or diagonally.

    For example, if you place the 7 as it is in the picture here, the other colored spots are the ones available for 6 and 8. The white spots are “off limits” for the consecutive numbers of 7.

    Play it alone or with your kids.

    The best part about this (and my friend’s class) is that you get to think about how you’re doing the puzzle. How do you process the rules and arrive at a solution?

    And then you can share your methods with others!

    This lets you (and them) discover new and curious ways of doing things — creating new neural pathways for more learning!

    Ask questions!

    If you get frustrated, don’t go right to googling the solution. First ask yourself these questions:

    • For each number, ask, “How many consecutive numbers does this have?” For example, 5 has two consecutive numbers — 4 and 6.
    • For each box in the puzzle area, ask, “If a number is here, where can its consecutive numbers go?”

    And there’s also these questions to ask as you work through:

    • Is there really a solution to this?
    • If there is a solution, is there any other solution?
    • Are there many solutions? How many?

    Get freaky!

    The 8 Digit Puzzle works great. But could there be a 6 digit puzzle with the same rules? Or a 7, 5 or 15 digit puzzle?

    Can you create it?

    Download the 8 Digit Puzzle Board & Numbers now and have fun. Don’t forget to share via Twitter/X. And let me know how it goes in the comments!

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  • 7 Rules of Life in Math!

    7 Rules of Life in Math!

    I’m not big on sappy sayings or lists. But when I saw a list of “7 Rules of Life” on Facebook, I couldn’t help but see the 7 Rules of Life in Math in it.

    1. Make peace.

    Did you have a math teacher laugh at you? Write him a letter and tell him he was a meanie.

    Did you have a math teacher say you weren’t good at math? Find her number, give her a call and let her know that she was wrong.

    Find a way to make peace with that past event.

    You’re not bad at math. You never have been. You just had some teachers that made you feel yucky.

    2. Ignore others.

    Forget about what others think. Your learning in math is your business.

    Don’t worry yourself wondering if you’re learning as fast as someone else. If you’re happy with your learning, that’s good enough.

    3. Give it time.

    Time helps — a lot.

    Learning isn’t something you sit and do today and then have in your brain forever. Often we put things in today and they don’t really make sense until 6 months from now.

    And practice over time helps it to gel. So be patient.

    4. Don’t judge.

    Just as your learning is yours, other people’s learning is theirs. If they don’t get it, avoid launching into the damaging “all you have to do is…” routine. Those words say, “Anyone can do this. It’s easy. And if you can’t, well… you’re an idiot.”

    Knock it off.

    Everyone learns differently — just because you get it quickly, doesn’t mean you get to be pushy about teaching it to others.

    5. Embrace ignorance.

    It’s okay to not know the answers. Math is about exploring. Discovering.

    If you don’t get the answer today, come back later. Don’t beat yourself up about it.

    In spite of what all the textbooks and teachers say, math is not linear. If you don’t get something today, keep rolling. It’s okay to skip it.

    When you least expect it, you’ll understand that “missing” concept so much better than if you tried for force yourself into it too soon.

    6. Take charge.

    No one’s in charge of your learning except you. Really.

    If you have to play the grades game, fine. But remember to learn along the way.

    Don’t jump through hoops for the sake of jumping.

    7. Smile.

    The next time you’re smiling, look around. There was math in what you did that made you happy.

    Maybe you saved 75% off a great dress. Or gotten to an event on time. Or had more people show up at your party than you expected.

    All of those are math. And you’re smiling about it!

    So keep smiling and share your thoughts in the comments or on twitter/x.

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  • Family Math Night — Nachos & Numbers

    Family Math Night — Nachos & Numbers

    I attended the Statewide Parent Involvement Conference in San Antonio this weekend. There I saw Thomas Ecker, award winning classroom teacher and author of Nachos & Numbers.

    Ecker developed the Nachos & Numbers Family Math Night (and the book) based on years of experience in classroom teaching and parent involvement.

    But the book Nachos & Numbers is so much more than a guide for an annual parent involvement Math Night event at a school.

    You can use the activities at home, in the car or anywhere the urge to learn strikes your child!

    It has activities for all areas.

    Chapter 8 of the book is full of activities perfect for a homeschool family, classroom or family game night. There are activities that promote basic numeracy all the way up to probability and statistics.

    In the session, we created some place value pocket charts (found on page 24). This is a simple and fun activity you could do at your kitchen table!

    Place value pocket charts work great for practicing place value — and you can cram them in your purse for some on-the-go educational opportunities.

    One of my favorite activities is “Expanded Notation in Expanded Form” on page 27. It’s an awesome way to show how a number can be written as the sum of its parts.

    It has a step-by-step plan for a Family Math Night.

    If you’re in charge of Family Math Night at your school or want to create a Math Night for your homeschool group — Nachos & Numbers is the best resource to make it happen.

    At just $12.50, it will be the cheapest thing you buy for Family Math Night!

    The other chapters cover getting support, publicizing your Math Night for optimum parent involvement, getting the right food and getting volunteers — everything you need!

    Get it!

    Whether you’re a parent wanting some ideas or a Parent Involvement Specialist tasked with putting on the annual Math Night, Nachos & Numbers is a must-have resource!

    (By the way, I paid full price for it. They haven’t given me anything to recommend this — I just think it’s super awesome!)

    Share your thoughts in the comments or on twitter/x.

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  • Logic Skills — Ornery Kids Develop them Naturally!

    Logic Skills — Ornery Kids Develop them Naturally!

    I got to see a natural use of logic yesterday — but it was disguised as an ornery kid!

    Parenting experts (and magazines) suggest that giving options to kids is a great idea — but only if they’re real. You’re not supposed to ask your little one if he wants to take a bath when you intend to give him a bath anyway.

    Instead, ask him which bathtub he wants to use. Or which towel he prefers when he gets out of the tub. Or even if he wants to take a bath alone or with a sibling.

    It’s a clever way of saying, “It’s time for your bath, but you get some autonomy in the activity.”

    Kids like this.

    And it’s formal math!

    Yup — in formal logic terms it looks like this: p∪q, where p and q are the options. And that little ∪ means “or.”

    For instance, I give K8 the choice of taking a bath alone or with me. So it looks like this:

    p = Take a bath alone.

    q = Take a bath with me.

    So p∪q = Take a bath alone or take a bath with me.

    But she’s more clever than I thought!

    Yesterday I gave her this option. She responded:

    I don’t want to take a bath alone and I don’t want to take a bath with you.

    Ornery little thing she is!

    But in our formal math lingo, this is

    ¬p∩¬q

    (Those little thingies in front of p and q are the “not” part. And the ∩ is the “and.”)

    If you look it up (or know formal logic) you can find out that ¬p∩¬q is exactly the same as ¬(p∪q).

    She was clearly saying to us that she does not want to take a bath at all!

    Math is built in.

    I’ve claimed before that we all have a built in ability to do math. Now it looks like that’s not just with numbers — it’s also with logical processing.

    She doesn’t get that she’s doing formal logic, but she understands in her gut that saying, “I don’t want to take a bath alone and I don’t want to take a bath with you” is negating the “take a bath” statement.

    Encourage it!

    I know it seems like she’s being a snot. And as she gets older it’ll get worse. I’ve seen my niece do it with my sister — play these logical games that feel like back-talk.

    But logic is the foundation of learning math. So instead of admonishing children, discuss it with them. Talk about a way to phrase your statements or rules so that there’s no logical loopholes.

    Allow them to argue with you on these little things — they’re building skills that will make them into super math thinkers!

    Your turn…

    What do you think? Has your child shown natural logic skills? How do you handle it?

    And how do I get K8 into the bath now!?

    Share your thoughts in the comments or on twitter/x.

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  • Number Jewelry — The Perfect Gift!

    Number Jewelry — The Perfect Gift!

    Have a math person in your life? Know anyone that has a favorite number?

    Head to the James Avery site to find charms of the numbers up to 99. Get a chain or dangle ring to put it on and you have a great favorite number gift!

    Want to go the full mile? Get a necklace and have the Fibonacci sequence put on it!

    And if your mom, teacher or partner isn’t into finite numbers, there’s also the infinity set!

    What numeral would you want?

    Share your thoughts in the comments or on twitter/x.

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  • Can every number be written as a palindrome in some base?

    Can every number be written as a palindrome in some base?

    My muse, Bartholomew, visited me this weekend with a question:

    Can every number be written as a palindrome in some base?

    What’s that mean!?

    Okay — first thing’s first. A palindrome is something that can be written the same way forward as backward. Like mom or 1001. Typically we ignore punctuation, so things like, “Go hang a salami, I’m a lasagna hog,” also count as a palindrome.

    And base means the number system — in our normal world we use base 10. Computers use base 2 (all ones and zeros) and hexadecimal (like the color codes you sometimes see on a computer — hex #ff9900 is the MathFour orange).

    Notice in hexadecimal — using 16 digits — we have to use letters as numbers. I did a video on base 12 arithmetic here — base 12 also uses some letters as numbers.

    So what’s the question again?

    Take any number — say 85. Can you convert it to some other base (like base 2 or base 7 or base 61) so that it looks like a palindrome?

    You can work hard converting numbers — or you can have a spreadsheet or Wolfram Alpha do it for you.

    If you use Wolfram Alpha, put in the statement “convert NUMBER base 10 to base NEW_BASE” — change the blue things, but leave the black ones the same.

    Notice if you convert 85 base 10 to base 84, the result is 1184 — which means every number can be written as a palindrome in the base that is one less than it.

    So 27810 is 11277. And 11 is a palindrome!

    So yes — every number can be written as a palindrome in some base.

    That’s a lame answer!

    You’re right. That’s what mathematicians call a “trivial” solution. It’s true, but it’s pretty lame.

    So let’s rewrite the question to be more interesting.

    Can every number be written as a palindrome in a base less than or equal to 10?

    This lets us use our “normal” digits — and it makes it more natural.

    I put together a spreadsheet to calculate some conversions. The yellow highlights are palindromes. The blue rows — those have no palindromes!

    Not every number can be written as a palindrome!

    That answers the question — but any good mathematician will ask the next question:

    What’s up with the numbers that can’t be written as palindromes?

    I did up to 100 and these numbers didn’t have palindrome conversions:

    19
    25, 29
    39
    47
    53, 58, 59
    69
    75, 76, 79
    84, 87
    90, 94, 95, 96

    Some are primes, some not. One’s even a perfect square!

    I leave the question with you…

    Any thoughts? What happens if you change the question again? Can you ask your children this question?

    Share in the comments — and don’t forget to tweet it!

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  • Seeing Rectangles in Rapunzel's Hair

    Seeing Rectangles in Rapunzel's Hair

    Part of Wordless Wednesday…

    I was walking out of her room when K8 shrieked, “A rectangle!”

    I looked and she was pointing directly at her Rapunzel bag. It took me a second, but I saw it when she said, “Her hair is a rectangle!”

    Amazing!

    Share your thoughts in the comments or on twitter/x.

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  • Why is the y-intercept called b?

    Why is the y-intercept called b?

    I’ve been teaching and tutoring the slope intercept form of the equation of a line for 25 years. That whole time I’ve wondered, “Why is the y-intercept called b?”

    Just today I discovered the answer!

    We teach it backwards.

    As is typical, we teach things in reverse of how we create them. The standard (or general) form of a linear function is

    f(x) = ax + b

    But this crazy f(x) notation isn’t really needed when you first learn to graph. We use y instead. So we have

    y = ax + b

    The nifty thing about this equation is that the number next to the x (in this case a) is the slope — or the measurement of how much the line tilts.

    The fancy letter for the slope is m. So we change the basic equation to include the slope notation…

    y = mx + b

    Turns out that the b here is also exactly where the line smacks into the y-axis — AKA the y-intercept. But there’s no fancy letter for that, so we just leave it as b.

    And we present that first!

    We tell early students of algebra that the slope intercept form of the equation of a line is

    y = mx + b

    where m = slope and b = y-intercept. But we don’t bother to tell them why we’re using such crazy letters!

    But now you have it. That’s the answer to the question, “Why is the y-intercept called b?”

    (If only we could figure out why they called the slope m!)

    Share your thoughts in the comments or on twitter/x.

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  • Multiplication Facts — Sevens

    Multiplication Facts — Sevens

    I was working with a tutoring client yesterday and we were focusing on the multiplication facts with seven.

    Instead of doing the basic chanting and quizzing, I decided to go a different route.

    We looked at the patterns.

    If you look at the last digit in the answers, you’ll see that every digit is represented:

    We continued to play with the answers and watched for patterns for the first digits.

    Then we looked at the multiplication facts from 11 through 20 using seven. The last digits on those followed the same pattern!

    Does this help memorization of the multiplication facts?

    Children feel the pressure of memorizing math facts. You can reduce this pressure by moving toward something more familiar or fun — like patterns.

    My client will still have to perform well on the multiplication facts test. But hopefully the fun we had with them will stick with her through it.

    How about you?

    Do you play with numbers and math facts? Do you help your children see the fun?

    Share your thoughts in the comments — and don’t forget to tweet it out too!

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