Teacher Guide: Subtraction to 20.

East West Math’s Subtraction to 20 Mastery Flash Cards© are designed to help students develop calculation strategies and master basic subtraction facts to twenty (20). Subtraction to 20 Mastery Flash Cards© focus on all teen numbers minus single-digit number facts that involve regrouping calculations and result in single-digit differences. The Subtraction to 20 Mastery Flash Cards© card set includes:

• A set of ten-frame cards (0 to 10)

• A set of teen number ten-frame cards (11 to 20)

• A set of subtraction cards (36 cards)* (see the notes in the next page)

• Subtraction to 20 Color-Coded Mastery Chart