MathShark plays like a video game and teaches like electronic flash cards with skill-building math practice PLUS a calculator all in one! This hand-held ELA randomly or sequentially quizzes kids on addition, subtraction, multiplication, division, fractiondecimals, or percentages with eight skill levels in each category. A no-fail game strategy along with lights and sounds motivate kids with instant feedback for self-directed practice. The LCD screen displays problems both horizontally and vertically.Lights and tones make math exciting and effective with non-stop feedback to build learning confidence. Sound can be turned off for silent classroom operation. A perfect skill-enhancing tool for all students from gifted to remedial. Class Pack includes 12 MathShark units. (Two AA batteries required in each MathShark, not included.) One year warranty.