There is No Such Thing as Subtraction

Intended Audience: All grades can use this activity in one form or another! It is a way to scaffold mathematical thinking using manipulatives. It can be used as an introduction to subtraction in the lower grades or an intervention for struggling learners in the later grades. The attached document can be used as a reading exercise for advanced student or its content can be used to help the teacher of the lower grades understand the concept better.

Concepts Presented: The document presents the additive inverse - the property of numbers that allows us to convert subtraction into addition. We can model subtraction of integers as addition of negatives with counters of two different colors. This activity presents an algorithm for turning subtraction into addition using the "Zero Pairs Method".

Mathematical Literacy and Rigor: Rigorous definitions and proofs are provided for higher level students however are not necessary for lower grades. Discussion/Reflection questions for the activity are also provided. Activity may be presented as a read-along, a teacher demonstration. There are exercises provided at the end for students to practice.

Lesson Outcomes:

• Student can add or subtract signed integers (elementary arithmetic)
• Student can model addition and subtraction using zero pairs (modeling/manipulatives/pictoral representation)
• Student will be introduced the concept of additive inverse (algebraic thinking)