Odds and Evens

I went and asked a few Grade 5 students to tell me about odd and even numbers, and this is what they said: Student A: “3 is odd, 2 is even”  Student B:“anything ending in a 0, 2,4,6,8 is even and anything ending in a 1, 3, 5, 7, 9” is odd. The students told me attributes of even and odd numbers, but not one of them explained to me the mathematical meaning of the terms.

The big understanding is that even numbers can be shared fairly into two groups whereas odd numbers always have a left-over and can not be split into two equal groups. I asked a grade 3 student and she explained it well, “Even numbers can be separated into two parts, like the number 8 produces 2 groups of 4, but odd numbers can’t be separated into two equal parts”. I was impressed that she had retained that understanding! When I asked a different grade 3 student to explain what it means to be even, he said, “I dunno”!

It is very important that we teach for understanding. This understanding starts in kindergarten and there are lots of fun ways to get children enthused. The trick is to find resources that show the meaning of odds and evens first. Then you can supplement with songs and stories that are about even and odd, even if they only talk about the numbers and not the big idea behind them.

My top choices are to give the students a manipulative such as Numicon blocks, which can easily be made out of 10 frames, and ask them to sort them into two piles. Students will usually sort those with bumps and those without. This leads to a deeper discussion about the concept of even and odd.

My second favourite way is to use twins. The twins are happy when they share evenly, but they are mad when they can’t and there is a left-over. Once I explain why they are feeling that way, the students can now discover which numbers are even or odd themselves. Watch as Rory easily conceptualizes the idea of two equal parts or left-overs.

Math is a beautiful subject full of patterns and connections and it is my responsibility as a teacher and a parent to make some of these connections transparent while I teach. At the end of this lesson, we tied it all together, labelled the numbers as even or odd and made some observations about the patterns (skip counting by 2) and connections we found. The fact that even numbers always end in certain numbers never entered our conversation, although it will eventually, when we recognize it as an observable pattern that we can use to predict whether something can be shared equally into 2 groups or not.

The next day Rory and I reviewed the concept by using dot cards. I chose this task as a follow-up for two reasons: he gains practice subitizing while reinforcing his understanding of odd and even. The cards we used come from a game called “Tiny Polka Dot”, but you can easily make your own set.


Students that gain a thorough understanding of the meaning of odd and even, can take their learning further. Now students have a starting place for harder problems that develop fluency such as: what happens when you add two even numbers together? What happens with two odd? Or even further: can you ever get an odd number when you multiply two even numbers together? What about multiplying an even with an odd? If the students have a better understanding of what it means to be odd and even, they can make some observations,  discover some patterns, and further develop on their number sense journey.

Tenzi Frenzy!

We are away for the summer at a cottage, with no internet or TV, which I usually love. We’ve already read lots of books, frolicked in the waves, swam to the Big Rock,  sailed to Seagull Island, canoed…dumped the canoe and had lots of good old fashioned fun; but my heart still felt the pitter-patter of excitement when I saw the clouds roll in, because that meant we could drive to the nearest town and spend the morning at Chapters!  

Don’t you love rainy days at Chapters? (Borders would probably be the US equivalent).The boys love playing with Thomas the train in the kids section, and looking at all the books, while I finally get a chance to peruse the latest best-sellers in person, instead of on Amazon! We go to the library every week, but it’s just not the same as a road trip to Chapters. And when we went yesterday, I felt like I hit the jackpot with my new find: TENZI!

Best. Game. Ever!!! Kevin and Steve (the game’s designers), made known by a little piece of paper in the game box with their story on it, may not have thought of the mathematical implications when they came up with the idea for the game, but kudos to them for unwittingly designing a brilliant game suitable for 3-103 year olds!!

Here is the general gist of the game, and I quote: “Everyone gets 10 dice. Then everyone rolls until someone gets all their dice on the same number.” Simple, right? Why am I so excited by this new find? Because of its GINORMOUS educational value! It’s like this game was conceived specifically with the pre-kindergarten to grade 2 curriculum in mind,  yet it’s intended for everyone!

Here’s why I love it:


Subitizing is the ability to recognize number patterns without counting. Rory quickly grasped what the dot patterns stood for and although he still counted the dots on each new turn, the repetition of looking for the same dot pattern reinforces his learning. I am confident that after a few more rounds, he will quickly and easily know the dot patterns for 1-6 without counting.

Counting on!

If you have 3 of the same number and get one more, now you have 4. Rory was learning and Practicing math skills without even knowing it! He already has developed one to one correspondence and cardinality, but now we’re extending his knowledge. What is 3 and 3 more, or 4 more, or 5 more?! Because each turn is different, he is continually practicing different amounts of counting on.

Decomposition and recomposition of 10 (a very important bench-mark number)!

Because the goal of the game is to get 10 dice all on the same number, you are constantly looking for two numbers that make up 10: those you already have with the same number on them and those you have yet to roll. Rory quickly saw when he needed one more to make 10, and then we looked to see that he already had 9. Or he had 5 of the same number and needed 5 more. And that leads to….


Decomposition of 10 is the building block to addition and although we didn’t concentrate on it today (it was our first time after all!), eventually we will use this game to practice our 10 facts. We can easily adapt it to practice our 5 facts first, just play with 5 dice each instead and yell, Fivzi!


This game is fun for the whole family!  Oliver got in on the action too but only to yell “Tenzi! “ and steal our dice to make a tower, but I’m sure he’ll see the math value soon!! It was me that finally drew the game to a close after almost an hour; Rory could have kept playing forever!

So Kevin and Steve (fortuitous mathematical master-minds that you are!), thank you for a fun and easy game that everyone can play. It looks like you two have a whole new market to exploit and hopefully I’ve inspired some new fans here!

If you want to know more, check out their website at www.ilovetenzi.com. Thank heavens for rainy days!!

Have other great math games that aren’t actually meant to be math games?

Post them in the comments section below!

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