The Tens System is the informal name for the most common grading scale used at educational institutions in the United States. It is also frequently encountered in many other countries as well, most notably Canada.
The system owes its name to the fact that each passing grade spans ten points, except for the "A" grade, which encompasses eleven. In the most common variant, the minimum passing mark is 60%.
The numerical ranges for each grade in the simplest version of the Tens System are:
90 to 100 = A
80 to 89 = B
70 to 79 = C
60 to 69 = D
Below 60 = F
The option exists to include "+" and "−" grades within each of the above categories (but customarily not in the case of the "F") so as to draw finer distinctions.
The most common method of doing this is:
97 to 100 = A+
93 to 96 = A
90 to 92 = A−
87 to 89 = B+
83 to 86 = B
80 to 82 = B−
77 to 79 = C+
73 to 76 = C
70 to 72 = C−
67 to 69 = D+
63 to 66 = D
60 to 62 = D−
Below 60 = F
Sometimes the "A+" range will be 98 to 100 and the "A" 93 to 97.
Not all institutions make use of the "A+" grade; this is most likely to be true if the grade point average system is in force. In that case, both the "A+" and "A" ranges shown above may become an "A," or the "A" and "A−" bands may be more evenly divided, say by calling 95 to 100 an "A" and 90 to 94 an "A−." In some cases an "A+" will be denoted on the transcript, but it will receive no advantage in calculating grade point average over the "A" grade (usually 4.0 out of 4).
At some schools — particularly parochial schools in the United States — the "D" grades shown above are omitted and the minimum passing grade is 70% instead of 60%, with any mark below 70 being an F (a few of these schools use "D" rather than "F" to denote failure).