Lesson Plans Course: Mastering Skills & Concepts: Course I Module ...

Lesson PlansCourse: Mastering Skills & Concepts: Course IModule: Addition and SubtractionUnit:SubtractionSession: Differences within 20Learning ObjectivesBuilding and completing number sentences involvingdifferences within 20.Recognizing and solving comparison problems involvingdifferences within 20.OverviewWe're looking at colorful butterflies at a butterfly farm. Wecompare the numbers of red and blue butterflies to find outhow many more red butterflies there are.KeywordsMoreTake awayTeaching StrategiesPrior to the sessionReview the subtraction facts for numbers within 10.Review the concept of one-to-one correspondence tocompare two sets and discuss how the two sets can bemade equal.At the end of the sessionRepresent the number of objects in two unequal sets anduse one-to-one correspondence and subtraction to find thedifference between them.Have students read and write an addition sentence for acorresponding subtraction sentence, e.g. 12 - 7 = 5 and 5+ 7 = 12.Give students various number sentences and ask them toconstruct take-away and comparison problems that eachmight represent.© 2001 Riverdeep Interactive Learning Limited. All rights reserved.