Learning the New England Patriots’ playbook isn’t easy.

Former Patriots wide receiver Malcolm Mitchell actually related learning the playbook to a rather difficult high school subject: calculus. He made the eye-popping comparison Thursday during his appearance on “The Michael Holley Podcast.”

“That was like calculus at the highest degree,” Mitchell said, per Boston.com.

The intricate plays Josh McDaniels uses to run his offense could’ve caused plenty of trouble for the young wide receiver, who at one time, had difficulty reading.

Mitchell improved his reading skills during the four years he spent at the University of Georgia and he credits that hard work with helping him learn the Patriots playbook.