Population of US = 300 Mn

Assumption that 1/4 is population between 0 and 18 (based on a research report I read) = 75 Mn

Assuming these are equally spread across ages 0 to 18, 0 to 6 has 25 Mn kids, or roughtly 4 Mn kids / age ( 1 year band applicable for KG)

For every 25 kids there are 2 teachers typically and to account for all other suporting teachers, adding 1 so 3 teachers for every 25 kids ==> 12 teachers for every 100 Kids. = 4,000,000/100 * 12 = 480,000 = .48 Mn teachers.

As there are typically two sessions - morning and evening in a KG day of only 3 hours, half the number of teachers is sufficient. = .24 Mn teachers.