Less Than Zero (Mathstart Series), Vol. 49 Stuart J. Murphy,
Perry the Penguin needs 9 clams to buy an ice scooter -- but he's not very good at saving. As Perry earns, spends, finds, loses, and borrows clams, a simple line graph demonstrates the concept of negative numbers.
10% Discount at Checkout. Just paste in the code we provide there.
We donate 7.5% of your net purchase price to provide student resources for the school or teacher of your choice. You can even direct part of the donation to pay student tuition or fees. Just follow the easy instructions on the checkout page.