The three classes of levers are:

  1. First-class lever — the fulcrum is in the middle.
  2. Second-class lever — the load is in the middle.
  3. Third-class lever — the effort is in the middle.

Quick memory tip

Think F-L-E :

  • F irst class: F ulcrum in the middle.
  • S econd class: L oad in the middle.
  • T hird class: E ffort in the middle.

Examples

  • First-class: seesaw, scissors, crowbar.
  • Second-class: wheelbarrow, bottle opener, nutcracker.
  • Third-class: forearm, sugar tongs.

If you want, I can also turn this into a one-line answer for homework or a simple diagram.