Thanksgiving 100, First Grade Addition upto 20 Worksheets, 100 First Grade Math Test Prep, 100, Thanksgiving Common Core Grade 1 Math Activities, Thanksgiving First Grade Math Sub Plan 1.OA.C.6 Add within 20 Size: Letter Paper sheet. It has 100 pages. Each sheet has 12 Equations. Answer Sheet for Teacher included. Ways Teachers Can Use the Maths Addition Worksheet Pack up to 20: In-Class Practice Homework Assignments Small Group Activities Formative Assessments Math Centers Timed Drills Interactive Games Individualized Learning Progress Monitoring