Start the practice of automated facts by systematic logic learning of simple facts. This series has flashcards for numbers up to 10 plus 10. Print them in card stock. The first two pages are the front of the cards, then you have to turn over the pages to print the answers in the back. Look for my series on other simple facts. After they have had enough practice with numbers plus one, they can practice numbers plus two, numbers plus 10, numbers that add up to 10, numbers plus 5. After that, you can teach numbers plus 9 because you can relate how they are almost like numbers plus 10, students just have to lower the other number by one and pretend it is plus ten. In a similar logic they can practice numbers plus 8. After you print both sides, you can laminate and cut the cards, punch a hole in the corner and place them in a ring for practice while they wait in line to go to the restroom and other down time occasions.