Subtraction Tables help children with the memorization of the essential equations of subtraction! Children can practice individual subtraction sets, such as 7-1, 7-2, 7-3, etc. The child can fill out the cards in any order they choose and can do so using the automatic or drag & place method. In a subtle way, the app keeps track of the child's progress, with a score or a timer, so parents and teachers can review their activity. Children can cycle through multiple cards that are randomized within each number set. Included is a set that includes randomized cards drawing from all the number sets (1-18). This activity is a time-tested method of reinforcing the basic differences of subtraction and is used in Montessori classrooms around the world! This app was co-developed and approved my an AMI certified Montessori teacher with over 40 years experience in the field! Thanks for supporting Mobile Montessori! www.mobilemontessori.org