12-digit scientific calculator is ideal for high school students, college students and professionals. Features two-line display, 419 functions, nine memories, last-digit correction and last answer recall. Multiline playback feature makes scientific equations easier for students to solve. After getting an answer, the student can then "playback" the expressions and substitute new numeric values. Direct Algebraic Logic allows students to enter the elements of an expression in the exact order they appear in the textbook. Calculator solves three equations at a time. Functions include 24 parenthesis levels, fraction calculation, metric conversions, DRG conversion, logic operators, one/two variable statistic calculation, and factorials. Twin power automatically switches from solar to battery power in low light. Hard cover protects calculator from scratches.