At some schools, especially in lower grades of elementary school, verbal assessment is used instead of traditional grades. For some purposes, this assessment may need to be converted to numbers.
Verbal assessment is more detailed than numerical grades and is difficult to convert unambiguously. Generally: "excellent" = 1, "very good" = 2, "good" = 3, "satisfactory" = 4.
If a student achieved excellent results in most areas, this can be considered a 1. If some areas were only good, it might correspond to a 2 or 3.