How many teachers are there in record?
select count(*) from teachers
What classrooms is CHRISSY NABOZNY in?
select classroom from list where firstname = "CHRISSY" and lastname = "NABOZNY"
How many are they?
select count(*) from list as t1 join teachers as t2 on t1.classroom = t2.classroom where t1.firstname = "CHRISSY" and t1.lastname = "NABOZNY"