Focus on Math

Helping children become mathematicians!

Jayden’s Rescue (Revisited) January 22, 2014

Screen shot 2011-05-31 at 3.46.07 PMI had the wonderful opportunity to be a guest reader in Mrs. DeGroot’s grade 5-6 classroom this morning. She was ready to start reading the novel Jayden’s Rescue by Vladimir Tumanov aloud to the class, and I had the privilege of starting it off. (See my previous post on the novel for more about the story and the math involved in it.) The students each had a copy of the Four Quadrants processing strategy (created by Susan Close and Carole Stickley) on which to jot ideas, important words, sensory information, and pictures that came to mind as the story was read.

We were also prepared to do the mathematical questions that would arise in the story as part of the rescue task.  The first problem that comes in the book is this:

I am the father of nine sons, all one-eyed monster boys.

I keep an eye on all my lads as they play with their toys.

A three-eyed monster once dropped in and brought his sons along.

Three bulging eyes were on each guest.

Oh! What a blinking throng!

Together all the monsters had exactly forty eyes.

How many three-eyed kids were there?

The numbers tell no lies.                              Jayden’s Rescue, p. 24

It took a bit longer than I had anticipated getting to that question on p. 24 (not to mention that that the lunch period began 15 earlier than I had expected it to!) so the students ended up not having a chance in the morning to share their solutions/strategies to the question. I left that in Mrs. DeGroot’s capable hands to finish up.

I believe the book is presently out of print, but copies are available from used-book sellers. It is definitely a book worth tracking down and reading to a class in the grade 4 to 6 range.

Mathematically yours,



12 Days of Christmas: Canadian Style December 11, 2013

Screen shot 2013-12-11 at 9.57.17 AMIf you are looking for a great Christmas-themed book for the young (or young at heart), you will want to check out A Porcupine in a Pine Tree: A Canadian 12 Days of Christmas (written by Helaine Becker, illustrated by Werner Zimmerman). Of course, the math connection is in the counting and in the adding up of all the items being given during the 12 days – all totaled it adds up to quite a tidy sum.

Certainly, any book with numbers tends to make me smile, but this one more than most. It is seriously delightful! It offers Mounties frolicking, squirrels curling, moose calling, hockey players a-leaping, and more.

The hardcover version is available from (not for the bargain price of $12.26 (price valid as of date of posting). Actually, for just a bit more, you can get the gift set version with the hardcover book plus an adorable little plush porcupine (sounds like an oxymoron doesn’t it!)

I am not affiliated with the author or publisher – I was given a copy of this book last year for Chrismas and I love it! I know you will, too.

May your days be merry and bright!

Mathematically yours,



Hat Tricks: Logical Thinking with Shadowchild May 21, 2013

Screen shot 2013-05-21 at 3.16.13 PM Anno’s Hat Tricks (by Akihiro Nozaki and Mitsumasa Anno) is a wonderful way to introduce children to the realm of logic and the powerful word “if”. The book goes through a series of “tricks”, all of which can be solved by applying that “mathemagical” word “if”– a word that opens doors to new ideas. Children are introduced to the concept of using “if” statements to test the truth of an idea or supposition in a logical way. The reasoning pattern of “if…then” can be very useful, and, indeed, branches of modern mathematics have been developed by applying the word “if”.

This delightful book is mainly about three children: Hannah, Tom (both of whom are clearly seen) and Shadowchild (who exists on the page only as a shadow). The writer gives a series of scenarios in which the reader is shown a certain number of hats (all either red or white) which are available, and then which ones of those hats are being worn by Tom and Hannah. We are to use logic to deduce what colour hat Shadowchild is wearing. Although the first number of scenarios in the story are quite easy, the difficulty level increases throughout the book, with the final trick being the most difficult. (If you are not sure of your own level of logical thinking, there are several pages at the end of the book devoted to parents and other older readers that will offer some assistance in the logic being applied in the different tricks.)

Sadly, I think the book is no longer in print, but it is well-worth your while to track down a copy. I know and your children will enjoy the challenges presented.
Mathematically yours,


Bean Thirteen — a Lesson in “Fair-Sharing” June 15, 2012

One of my recent purchases was the delightful book Bean Thirteen by Matthew McElligott. The story tells the tale of Ralph and Flora, two bugs who were picking beans for dinner. Ralph warns Flora not to pick the thirteenth been (as it is unlucky!) but as Flora does not agree with Ralph, she goes ahead and picks bean the thirteenth bean. Then dilemma begins. If they split the beans between them, bean 13 is left over. If they invite one, two, or four friends over to share the beans with, bean 13 is still left over. (And there was real trouble when they only tried to invite 3 friends over!) The final solution for the problem is a real-life example of problem solving at its best. Bean Thirteen is a great book to use for developing the concept of division for K-3 students.

After reading the book to my two grade 2 classes, I had them do an activity based on the book. Students each counted out 18 bingo chips to represent beans, and then they were asked to share them on “plates” for different numbers of friends. I provided cut up pieces of construction paper to represent the plates, and the students shared out the beans equally on the plates. (We called this “fair-sharing”.) Beside the number of plates (or number friends sharing) listed on the recording sheet, students wrote down the number of beans on each plate and the number of beans (if any) left over.

Because of the concrete nature of the activity, everyone was able to be successful. Early finishers were allowed to take a different number of “starting” beans and explore what would happen when that number of beans was shared.

If your school library does not have a copy of this book, ask your librarian to order one in. It is well worth having.

Mathematically yours,

Download the full-sized activity sheet here.


Fibonacci Numbers: A Fascinating Sequence January 10, 2012

I was recently given the gift of this delightful interactive book written by Emily Gravett. Although it appears to be a children’s book, The Rabbit Problem can be appreciated on the adult level as well. This tale of Lonely Rabbit and Chalk Rabbit is actually a retelling of a scenario that, according to Wikipedia, first appeared in the book Liber Abaci (1202) by Leonardo of Pisa, known as Fibonacci. Fibonacci considered the growth of an idealized (biologically unrealistic) rabbit population, assuming that: a newly born pair of rabbits, one male, one female, are put in a field; rabbits are able to mate at the age of one month so that at the end of its second month a female can produce another pair of rabbits; rabbits never die and a mating pair always produces one new pair (one male, one female) every month from the second month on. The puzzle that Fibonacci posed was: how many pairs will there be in one year?
•    At the end of the first month, they mate, but there is still only 1 pair.
•    At the end of the second month the female produces a new pair, so now there are 2 pairs of rabbits in the field.
•    At the end of the third month, the original female produces a second pair, making 3 pairs in all in the field.
•    At the end of the fourth month, the original female has produced yet another new pair, the female born two months ago produces her first pair also, making 5 pairs.
The question, of course, is how do we know how many pairs of rabbits there will be at the end of any given month??***
The answer lies in the Fibonacci sequence of numbers, a fascinating set of numbers that keep popping up in nature in amazing ways. The sequence begins with 0 (or should I say “can begin”?), then add 1, and from there the next number in the sequence is always derived from adding the two previous numbers. So the third number is 0 + 1 or another 1, the fourth number is 1 + 1 or 2, then 1 + 2 or 3, then 2 + 3 or 5 and so forth, giving this sequence:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610 …
I recommend this short  video by Vi Hart to jumpstart your thinking about these numbers (it’s about 6 minutes long). She builds the topic of Fibonacci numbers off the topic of spirals, so be patient and the number part will come. As you watch, keep in mind the kinds of explorations that you and your class can pursue with pinecones, pineapples, artichokes, cactus fruit, flowers, and such. Often the number of seeds that show up in fruit and vegetables is a Fibonacci number. Try counting the seeds of the next apple or orange you eat!
This website has a whole host of information about connections to the Fibonacci series. Note especially the section about plants. You might be able to do some of your explorations from the photos included here is real fruit, pine cones, etc are not readily available.
Exploring Fibonacci numbers can be a great “hook” to grab students’ interest about numbers and mathematics.
Mathematically yours,
***By the way, the answer the the rabbit question is this: at the end of the nth month, the number of pairs of rabbits is equal to the number of new pairs (which is the number of pairs in month n − 2) plus the number of pairs alive last month (n − 1). This is the nth Fibonacci number.