Flashcards based on number bonds for addition, using a length-based representation to build students' intuition for the meaning of addition. Not drawn to scale so that students must remember or calculate, rather than visually measure. Students should be able to figure out any number, when covered, by adding or subtracting the other two as appropriate.
Trial version includes ten cards. Full version will include all number bonds up to a sum of 20, plus complete instructions, including how to print sets of cards needed for your curriculum and level.
Related to Common Core Math Standards for K-2; grades above second can use these cards for review and improving recall time.