## Lesson: Modeling Subtraction

Developing the Concept

Once children have had practice subtracting from numbers to 6, you can introduce the concepts of zero in subtraction, subtracting from numbers to 8, and writing subtraction sentences vertically. Finally, provide children with exercises for which they must choose the operation.

**Materials:** overhead projector, 8 overhead counters, blank overhead transparency; Workmat 1, 8 counters, number and symbol cards and Subtract From (PDF file) worksheet for each child; 2 spinners (0–8) for every 2 children

**Preparation:** During the lesson, be prepared to give each child a set of number and symbol cards and later 8 counters and a copy of Workmat 1. Prepare Subtract From (PDF file) worksheets for each child. Make spinners with numbers 0 to 8 for each pair of children.

**Prerequisite Skills and Concepts:** Children should be proficient in counting and recognizing numbers to 10. Children should demonstrate an understanding of finding sums to 8 and subtracting from numbers to 6.

**Wrap-Up and Assessment Hints**

You can assess children's understanding of addition and subtraction as well as their ability to choose the correct operation by providing them with two spinners (0–8). Have the children spin the first spinner and record the number. Then have them spin the second spinner and decide whether they need to add to or subtract from the first number to get the second number. Have children record their number sentences.