There are numerous differing types of double facts. A number of the commonest kinds contain multiplication facts, addition facts, and subtraction facts. In addition, You will also find double facts that require fractional figures and decimal figures. The anchor charts on this site give examples of 5 subtraction strategies that https://www.generationgenius.com/videolessons/strategies-to-add-subtract-within-20-make-a-10-doubles-facts/