The grading system is basically similar everywhere
Sometimes there is a bit of a difference between the numbers at individual universities. Look at the ones for U of T not for BC.
The letter characters and the numbers are there for individual tests and for course final grades. The numbers tell you how your grade is being determined.
The GPA is your Average as determined by the administration not by your professors.
For example, if you look at the first Table in the link to the U of T Word document, you can see clearly that
A+ is 90 to 100
A is 85 to 89
A - is 80 to 84
C+ is 67 to 69
The GPA point value is the same only for the two top grades.