How to Use a Scientific Calculator

How to Use a Scientific Calculator You might know all the formulas for math and science problems, but if you dont know how to use your scientific calculator, youll never get the correct answer. Heres a quick review of how to recognize a scientific calculator, what the keys mean, and how to enter data correctly. What Is a Scientific Calculator? First, you need to know how a scientific calculator is different from other calculators. There are three main types of calculators: basic, business, and scientific. You cant work chemistry, physics, engineering, or trigonometry problems on a basic or business calculator because they dont have functions youll need to use. Scientific calculators include exponents, log, natural log (ln), trig functions, and memory. These functions are vital when youre working with scientific notation or any formula with a geometry component. Basic calculators can do addition, subtraction, multiplication, and division. Business calculators include buttons for interest rates. They typically ignore the order of operations. Scientific Calculator Functions The buttons may be labeled differently depending on the manufacturer, but here is a list of common functions and what they mean: Operation Mathematical Function + plus or addition - minus or subtraction Note: On a scientific calculator there is a different button to make a positive number into a negative number, usually marked (-) or NEG (negation) * times, or multiply by / or à · divided by, over, division by ^ raised to the power of yx or xy y raised to the power x or x raised to the y Sqrt or √ square root ex exponent, raise e to the power x LN natural logarithm, take the log of SIN sine function SIN-1 inverse sine function, arcsine COS cosine function COS-1 inverse cosine function, arccosine TAN tangent function TAN-1 inverse tangent function or arctangent ( ) parentheses, instructs calculator to do this operation first Store (STO) place a number in memory for later use Recall recover the number from memory for immediate use How to Use a Scientific Calculator The obvious way to learn to use the calculator is to read the manual. If you got a calculator that didnt come with a manual, you can usually search for the model online and download a copy. Otherwise, you need to do a bit of experimentation or youll enter in the right numbers and still get the wrong answer. The reason this happens is that different calculators process order of operations differently. For example, if your calculation  is: 3 5 * 4 You know, according to the order of operations, the 5 and the 4 should be multiplied by each other before adding the 3. Your calculator may or may not know this. If you press 3 5 x 4, some calculators will give you the answer 32 and others will give you 23 (which is correct). Find out what your calculator does. If you see an issue with the order of operations, you can either enter 5 x 4 3 (to get the multiplication out of the way) or use parentheses 3 (5 x 4). Which Keys to Press and When to Press Them Here are some example calculations and how to determine the correct way to enter them. Whenever you borrow someones calculator, get into the habit of performing these simple tests to make sure youre using it correctly. Square Root: Find the square root of 4. You know the answer is 2 (right?). On your calculator, find out whether you need to enter 4 and then press the SQRT key or whether you hit the SQRT key and then enter 4.  Taking the Power: The key may be marked xy or yx. You need to find out whether the first number you enter is the x or the y. Test this by entering 2, power key, 3. If the answer was 8, then you took 23, but if you got 9, the calculator gave you 32.10x: Again, test to see whether you press the 10x button and then enter your x or whether you enter the x value and then press the button. This is critical for science problems, where youll live in the land of scientific notation!Trig Functions: When youre working with angles, keep in mind many calculators let you select whether to express the answer in degrees or radians. Then, you need to determine whether you enter the angle (check the units) and then sin, cos, tan, etc., or whether you press the sin, cos, etc., button and then enter the number. How do you test this: Remember the sine of a 30-degree angle is 0.5. Enter 30 and then SIN and see if you get 0.5. No? Try SIN and then 30. If you get 0.5 using one of these methods, then you know which works. However, if you get -0.988 then your calculator is set to radian mode. To change to degrees, look for a MODE key. There is often an indicator of units written right up with the numerals to let you know what youre getting.