This is a great Phonemics Awareness skill, alphabetical order skill and otherwise gets skids thinking where letters come in the alphabet. Give 4 to 6 to start until they are learned. For each missing letter deck level. Go on to the next level and sos on until all cards are mastered. . I received this information with my Orton Gillingham training over a decade ago. It is wonderful for children to work at individually as a P.A. skill or warm up, or to keep in folders for seatwork.