C2.1 Identify quantities that can change and quantities that always remain the same in real-life contexts.
Skill: Determining Which Quantities Change and Which Remain the Same in Daily Life
Students live in a changing world. Understanding that change is a part of life and that most things change over time (for example, each year their height and weight increases and their feet get longer) is the final component of developing algebraic thinking.
The observed changes can be described qualitatively (I am taller than last year, my hair is longer, it is colder than this morning) and quantitatively (I have grown 2 cm this year, the temperature has dropped 6°C in 3 hours).
Source : Guide d’enseignement efficace des mathématiques de la maternelle à la 3e année, p. 21.
It is also important to have students observe, in their daily lives, that there are quantities that do not change. This awareness will help them better understand the concept of constancy later in their learning.
Finding quantities in everyday life that stay the same and quantities that can change will help students understand the concept of variable.
Source : The Ontario Curriculum. Mathematics, Grades 1-8 Ontario Ministry of Education, 2020.
Knowledge: Constant
Quantities that do not change are called constants.
Knowledge: Variable
The quantities that can change are called variables.
Source : The Ontario Curriculum. Mathematics, Grades 1-8 Ontario Ministry of Education, 2020.