Shark Swimathon (MathStart)

by Stuart Murphy; illustrated by Lynne Cravath

"Sharks, sports, and subtraction--it's a winning combination!" (Booklists)  This book is a cute Math Start book that's great for teaching early lessons on two-digit subtraction.

In the story, the Ocean City Sharks are preparing for the Shark Swimathon so a local bank offers to sponsor them if they can swim 75 laps by the end of the week. To meet their challenge, they swim every day and use subtraction to figure out how many laps are left to go.

The two digit subtraction problems are discussed and written on a board by the coach -- which really helps drive home the subtractions problems for readers!   School Library Journal said "this entertaining story would work well as a supplement to lessons on two-digit subtraction." We agree. It's great for showing a 'real world' application, and could easily be extended into a hands on activity.

Reading Levels

Interest Level:  Grade 1-3
Grade Equiv: 2.7

DRA Level:  18
Guided Reading:  K

Lexile Measure: 380L

See Inside

Below are typical spreads from inside this book. It's a cute story, although a little wordy. To read the text, you can click on the image to make them larger. In short, in the spreads below, the Ocean City Shark swim team is excitedly talking about attending the state swim camp but soon realize that in order to attend, they will need money to get there and money for lunches (especially since "they were always hungry.")  So, they come up with a solution that requires lots of math!  :)

To learn more about this book, click the link below.  (Please note that if you purchase an item from Amazon, they will give me a small referral fee.)



Shark Swimathon Lesson Ideas

On his website, the author suggests a fun two digit subtraction activity that you could play after a read-aloud of this book: "Provide 8 dimes for each player, 50 pennies for the "bank," and create a set of cards numbered 1 through 15. Each player starts with 8 dimes. Mix up the cards and place them face down in a pile. Taking turns, players draw a card and give the amount shown to the bank. If a player does not have exact change, he or she must exchange one of their dimes for 10 pennies. The first player to get rid of all his or her money wins."

Do you use this book in your classroom (or homeschool) for teaching two-digit subtraction. If you do, and you have an extension idea or activity to go with it, please let us know so that we can share it on this page with all users of this site.


To learn more about this book, click the link below.  Please note that if you purchase an item from Amazon, they give us a small referral fee. (This helps pay for site hosting costs, thus allowing us to keep everything free for site visitors!)



This book is one of the MathStart series books. We LOVE the MathStart series. The stories are funny and cute...and SO effective for teaching the specific math concept being targeted. You can learn more about this great series of books by clicking on the book covers below or the link above.