Wedge the large plastic opening tool in the gap at the bottom between the top and bottom covers.

Apply a gentle downward force to separate the top cover from the bottom cover.

Wedge the large plastic opening tool in the gaps along each side to unhook the side clips.

There are clips located at the bottom of the calculator, on the sides of the calculator (both near the bottom and near the top), and at the top of the calculator.

Pull the bottom cover apart from the top cover.