One is a Snail, Ten is a Crab: A Counting Feet Book

When you are counting by feet, then 1 is a snail, and 2 is a person, and 4 is a dog! This book uses the number of feet on various animals as the units by which numbers can be expressed. So for example, “40” can be 10 dogs (10 x 4), or 20 people (20 x 2), or 6 insects and a dog (6 x 6 + 4). The book is a humorous and colourful illustration of part-whole thinking.

Prior to this lesson, you can have created copymasters of your own children’s drawings of the “units” (snail, person, dog, insect, crab) by asking someone to draw one of each and then reproducing them on a photocopier to create sheets of units, or you can use the copymaster of clip art “units”, or you can have each child do their own drawings for the activity.

1.

Prior to reading, warm up with some number recognition and partitioning questions. Play “Guess My Number” with the hundreds board by choosing a “mystery number” in your mind and having students ask questions to narrow the search for the mystery number (does it have a 2 in the ones column? etc.).

Reverse the game and give clues that help them narrow the search for another number.

For example:

• My number has an even number in the tens column, or
• My number is 4 more than a tidy number, or
• My number is made up of two digits that are the same, and so on.

2.

Share the book with your students, stopping to record the mathematics on each page.

For example, 6 is 3 people, or a dog and a person, or 1 insect.

• How would we write those? 3 people is 3 x 2, 1 dog and 1 person is 4 + 2, and 1 insect is 1 x 6.
• Is there any other way we could make 6?

3.

After reading the book, explain to students that they (or their pair) will each get to pull a number from the bag and make that number in 2 ways using the counting feet from the story.

4.

Model one example for them by taking a piece of A4 or A3 paper and folding it in quarters. Unfold and record the following labels, 1 per quarter:

• My Number
• Words
• Picture
• Equation

Turn the paper over and label the same on the other side.

Select a number from the grab bag, and with their support, fill in each quarter. For example:

Then ask:

• What is another way I could make 63?

Show them how you would do it the other way on the reverse side of the paper.

5.

Students then draw numbers from the bag and use the materials provided to make a two-page “Number Footprint”. Circle the numbers that have been drawn out on the hundreds board as students may want to make more pages later as an independent activity and then can select numbers not already illustrated.

6.

Compile all the pages together to publish a class book.

7.

As an extension or follow-up activity, you can investigate other units such as octopus, centipede, or starfish and explore the multiples of each unit by itself before combining with others.