Style: EL-W516TBSLAdvanced, 4-line scientific calculator with WriteView display, allows calculations to be entered and displayed as written they would appear in a textbook. With 640 functions, the EL-W516TBSL is ideal for professionals and students studying general math and science, pre-algebra, algebra I & II, geometry, pre-calculus, calculus, trigonometry, statistics, biology, chemistry, and physics. Features a durable matte black finish with silver accents and operates on twin-power (solar with battery backup).