Illustrative Mathematics
Illustrative Mathematics: "One More" Concentration
This game is a version of the traditional memory or concentration game. Young scholars will practice counting forward or backward depending on their skill level. Directions and materials needed are fully explained in the lesson.
CK-12 Foundation
Ck 12: Elem Math: Completing the Addition Sentence Sums to 20
[Free Registration/Login may be required to access all resource tools.] The video shows how to count backwards to determine the missing number in an addition problem. The video is followed by practice problems to assess student...