Course Guide - USAID Teacher Education Project

Unit 1 Number and OperationsWeek 5, Session 2: Operations with Integers18. Maths Processes to be studied• The goal for this lesson is to have students develop algorithms for operationswith integers by engaging in various activities. This is in contrast to simplymemorizing the rules versus understanding underlying concepts so well thatstudents can reconstruct the rules when necessary.• Operations are actions. In the models and activities described below, there is adistinction between the negative sign of a number and the minus sign indicatingthe operation of subtraction. Thus, students will physically move objects or actout the operations to build their understanding. These would include actuallywalking on a number line in prescribed ways to model addition and subtractionwith integers, and moving 2-colour chips into zero-sum pairs.• Different operations are best served by different models:o When using (and actually “walking” on) a number line to model an equation,there are two “directionalities” that we need to consider: a) the sign for thenumber, the direction to which we “face”: positive (right), negative (left)versus b) the sign for the operation, an action (in which direction we “walk,”forwards or backwards).We will be using variations of one basic equation to explore the concept ofadding and subtracting integers with the goal of students seeing patterns andcoming to generalizations.1. For example, to model the equation (-4) + (-2) = x, I would start bystanding at -4, the first number in the equation looking toward the left of 0,in the negative direction. Then I consider the second term. Because it is -2,I would stay turned in that negative direction.Once I have the signs of my numbers in place, I need to consider theoperation. Since the operation is addition (+) I walk forwards and land on -6.