The site is organized by grade and activities are aligned to the Common Core State Standards (CCSS). Within the navigation the activities are further classified under headings such as Operations & Algebraic Thinking, Number & Operations in Base Ten, Measurement & Data, Geometry. You can drill down further to a specific standard for the grade. Clips can be categorized as SUPPORTS, MEETS or EXTENDS a standard so teachers have flexibility to select activities that suit the mixture of student abilities in their classroom.
You can preview the standard and activity overview by clicking on more... in the descriptive text.
SUPPORTS 1.OA.A.1: Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.