Having the same number of students in each row, 80 students can be arranged in 80 rows of 1, 40 rows of 2, 20 rows of 4, 10 rows of 8, and 5 rows of 16.
10 rows and 80 columns
There are no smaller arrays. If the number of rows is smaller then the number of columns is larger and, conversely, if the number of columns is smaller then the number of rows is larger.
Groups
divide the smaller number by the larger number, and multiply by 100. 60 is 75% of 80.
You would get 80%. To get percent, divide the smaller number by the larger number and multiply by 100. Thus: 15/18 = 0.8 x 100 = 80%.
80 divide by 30 = 2.6666666666666665
If you divide plants into four rows of three plants each, you would need 12 plants. With seven plants, you could divide them into two rows with 3 in one row and 4 in the other, plant them all in one row, make 3 rows with 2 in two rows and 3 in one row, etc.
90000
Divide by 80.
They can divide by ten.
Around 80-85.