Answer:
216 calls
Step-by-step explanation:
if the principal calls 6 teachers, who also call 6 on their own, that is [tex]6*6=36[/tex] calls made. if each of those 36 teachers call 6 more teachers, its saying [tex]36*6=216[/tex] calls in the last group.
if you need total calls, you would have to add each group together meaning, [tex]1+6+36+216=259[/tex] total calls