The phrase "all three grades" is correct and usable in written English.
It can be used when referring to a specific set of three grades, such as in an educational context or when categorizing items.
Example: "The students in all three grades participated in the science fair this year."
Alternatives: "the three levels" or "all three classes".
"We believe this will foster community among students throughout all three grades".
Methamphetamine use is now highest in rural areas among all three grades and heroin use is about equal in urban and rural areas, the survey found.
Over all, the science scores of black and Hispanic students remained well below those of white students in all three grades.
At Negeri 2, a senior high school with more than 1,000 students, Chinese became mandatory for all three grades starting this school year.
Mirroring national results, roughly equal percentages of boys and girls performed at proficient on Indiana's math assessments in all three grades.
She planned a new school routine that blended all three grades in each classroom, so the sixth graders, evacuated on their fourth day of middle school, had the support of the older children.
Rather, there was rough parity in the percentage of boys and girls reaching proficiency at all three grade levels and no state had a difference in math between girls and boys of more than 10 percentage points.
District priorities drove the changes that included incorporating math tasks from the UUSD curriculum at all three grade levels and focusing significant attention to the needs of ELs.
"Contrary to popular assumption, at all three grade levels African American youth have substantially lower rates of use of most licit and illicit drugs than do Whites". Monitoring the Future Survey, 2004.
In all three grade III anaplastic ependymomas, the percent of tumour nuclei staining positive was only 10 20%.
