Mathematics 5 curriculum guide 2015 I table of contents acknowledgements

5PR1 Continued...
In Grade 4, students used symbols in expressions such as 4 + 
∆
. In 
Grade 5, lower case letters will be used for the variable. It will be 
necessary for students to see how 4 + 
∆
= 7 means the same as 4 + 
n
= 7. 
This will be students’ first formal exposure to the use of letters as 
variables to represent an unknown number. A variable is a letter or 
symbol used to represent an ‘unknown’. Patterns using symbols and 
variables provide a means of describing change mathematically (e.g., two 
more than a number (
n
+ 2) or six less than a number (
h
- 6)).
A number sentence is called an equation. A number sentence with 
a variable is an algebraic equation. The major difference between an 
equation and an expression is that an equation is a complete sentence 
which says two things are equal. It contains the verb ‘equals’. For 
example, 
h
+7= 10 means a number
 h
added to 7 is equal to 10. 
Students worked with equations in Grade 4. An expression also contains 
numbers and variables but there is no ‘equals’. For example,
p
+ 3 is 
read as the number 
p
added to three. There is no mention of being equal 
to something else. 
In mathematics, variables are typically quantities that change. Students 
might relate variables to things from their own experiences which 
change over time, such as their height or hair length.
In the early stages of variable usage it may be wise to avoid the use of 
“x
” or “
s
” as variables, since students often get “
x
” mixed up with the 
multiplication symbol and “
s
” can be confused with the number five 
when written by hand. It is important, when reading aloud to students, 
to read expressions such as 3 + 
m
as “a number 
m
added to 3,” or “3 
more than 
m.
”