When I was in high school, I used a Texas Instruments scientific calculator. \u00a0What model it was I don’t know, but it was virtually the same as today’s TI-30XA.<\/p>\n
Back then, the calculators I knew of were all reverse entry: \u00a0<\/em>when you wanted to take the square root of a number, you’d enter the number first, then tap the square root key. You’d take sin, cos, or tan of an angle the same way: \u00a0by entering the number first, then the function. \u00a0My Texas Instruments TI-30XA and Casio fx-260SOLAR are both reverse-entry.<\/p>\n Among the calculators I see people using nowadays, reverse-entry ones constitute the minority. \u00a0More of my students use\u00a0forward entry<\/em>\u00a0calculators: \u00a0to get the square root of a number, they tap the square root key, follow by entering the number, then press the “equals” button. \u00a0The same goes for sin, cos, and tan: \u00a0they enter the function, then the number, and finally “equals”.<\/p>\n Most people know which type of calculator they have and how to use its basic functions. However, some may not realize how their calculator handles brackets. \u00a0For example, 4(7+3) means 4x(7+3) to a human. \u00a0However, neither my TI-30XA, nor my CASIO fx-260SOLAR recognizes that the brackets mean multiplication. \u00a0Each requires you to enter 4x(7+3) in order to recognize you intend to multiply.<\/p>\n On the other hand, my forward-entry SHARP EL-520W does accept 4(7+3) as meaning 4x(7+3); it will give 40 when you enter 4(7+3)=. \u00a0However, it will not do so when you enter (7+3)4=.<\/p>\n There are many models of calculator in use today. \u00a0A student will do well to experiment with his or hers, to be sure of how it interprets brackets and\/or expects functions to be entered. \u00a0While many are similar, you can’t always safely assume that your new one works just like your old one.<\/p>\n More differences among various models of calculator will be explored in future posts:)<\/p>\n