Smarter Balanced
Classifying Vertebrates
What features do scientists use to classify animals into groups? Class groups examine a series of paired images of vertebrates (a bass and a trout, a toad and a newt, a crocodile and a tortoise, an owl and a robin, a tiger and a bear)...
Virginia Department of Education
Ground Zero
Don't harbor any negative feelings toward negative numbers. Scholars learn about different classifications of rational numbers, including negative integers. They also develop definitions of the opposite and the absolute value of a...