Models of Subtraction

Learning the four models of subtraction enables children to fully understand subtraction used in problem solving, various operations, and in everyday life.

Take Away: taking a small set from a large set.

Separating: 2 small sets within a larger set.

Missing Set: empty spaces in a large set.

Matching Sets: comparing 2 separate sets

If sets are not clearly understood, group/s can be substituted for set/s. After explaining the four models, examples should be presented. It takes a while for children to realize that the numerical answer is not the answer – you want to hear which model it is. The following are some examples, first for a mother with a child or two and then for a teacher with a class:

Mother, for take away: Katie has 5 brothers.  Two brothers went outside to play.  How many brothers are still in the house?

Mother, for separating: There are 6 red and blue balls. Two of them are red. How many are blue?

Mother, for missing set: The table is ready for 4 people for dinner. One person is already sitting down. How many more people can sit at the table?

Mother, matching sets: There are 3 chickadees and 2 blue jays at our feeder. How many more chickadees than blue jays are at our feeder?

Teacher, for take away: There are 20 children in our class. 5 children are going to the library. How many children are left in the class?

Teacher, for separating: There are 6 children in the library. 4 of them are girls. How many are boys?

Teacher, for missing set: There are 8 chairs at a table. If 5 chairs are occupied, how many more chairs are empty?

Teacher, for matching sets: There are 5 children reading and 4 children writing.  How many more children are reading than writing?

Again, it takes practice for children to answer which model it is. But when children are easily able to give the correct model, they will fully understand the use and purpose for subtraction.

Read more about teaching Math in my book, Early Childhood Programs: Opportunities for Academic, Cognitive, and Personal Success, beginning on page 113. Also, see 7 reviews on www.amazon.com

   Teaching Young Children © Peggy Broadbent 2011 - All Rights Reserved