How to Use the OGT Calculator
		Add, subtract, multiply, divide Percent Key Negative numbers Pi Key Raising to a Power Key Cube Root Key Squaring Key FIX Key Factorial Key Memory Key: X store into Memory , Recall from Memory Parentheses Keys Degrees-Minutes-Seconds Key Degree Key Trigonometric Function Keys: Fractions

, ,

is the "All Clear" key. It clears out the number being typed in and resets the calculator so that all the settings are the original settings. It is strongly suggested that you press the key when you wish to start a calculation over or when you are unsure in what mode the calculator is.

NOTE: Press the key to restart the calculator. Sometimes you may want to press the key when you start a new calculation.

is the "Clear / Clear Entry" key. Press one time and this will clear the current number being entered into the calculator. Press a second time and this clears the number being entered and the entire calculation being done.

is the backspace key that you can use when you are entering a number and just made a mistake on the last digit or two.

Example. Press . Then type in this number: 987654321 Then press the . Notice that it backspaces and deletes the last digit, the ‘1’, that you typed. If you press again, it backspaces and deletes the ‘2’ This is a helpful key to use when you are working with very large numbers.

Add, subtract, multiply, divide

Example: 0.9 X 0.13 = ?

Press these calculator keys: 0.9 0.13 Calculator shows this result: 0.117

Problem: 34.8 + 1.57 = ?

Press these calculator keys: 34.8 1.57 Calculator shows this result: 36.37

Problem: 3500 - 51.7 = ?

Press these calculator keys: 3500 51.7 Calculator shows this result: 3448.3

Problem: 50 ÷ 12 = ?

Press these calculator keys: 50 12 Calculator shows this result: 4.166666667

Note: The OGT calculator displays 10 digits being for this answer. The OGT calculator will display up to 10 digits of accuracy. The actual answer is 4. 1666... or 4.16, which means that the "6" repeats an infinite number of times. The calculator rounds the 10th digit to a "7" because it cannot repeats 6's forever.

Percent Key

The % key is located in green above the key.

The only thing this key will do is rewrite a % as a decimal. For example, if you type in 6 and then type the % key, the result is 0.06 (recall that % means "out of 100" or "x 0.01"). This is all this key will do.

Problem: Rewrite 25% as a decimal.

Press these calculator keys: 25 Calculator shows this result: 0.25 because 25% is 25 out of 100 or 25/100 which is 0.25.

Problem: Rewrite 3% as a decimal.

Press these calculator keys: 3

Calculator shows this result: 0.03 because 3% is 3 out of 100 or 3/100 which is 0.03.

Problem: Rewrite 1/2% as a decimal.

Press these calculator keys: 1 2

Calculator shows this result: 0.005 because 1/2% is the same as 0.5% which is 0.005.

Problem: Rewrite 12.5% as a decimal. Calculator shows this result: 0.125

Negative numbers

To type in a negative number, you type the number first, THEN the negative sign second.

Problem: -237 ÷ 5 = Calculator shows this result: -47.4

Find the key. It is located in the middle of the bottom row of keys on the calculator. Pressing this key takes the opposite of the number that is in the display of the calculator.

For example, to multiply -18 by -5, the keystrokes are as follows: 18 [ 5 ] Calculator shows this result: 90

Problem: 481 x -18 = Result is -8658

Problem: 71 ÷ (-8) =

Press these calculator keys: 71 8 Calculator shows this result: -8.875

Pi Key

The π key is a "green" key, so you must press the green key first to tell the calculator you want to use the key. The key is located in the fourth row, first column, above the key.

Press these calculator keys: Calculator shows this result: 3.141592654

Note the calculator displays 10 digits.

Raising to a Power Key

Problem: 4³ = ?

Press these calculator keys: 4 3 Calculator shows this result: 64

Problem: 2.7⁴ ?=

Press these calculator keys: 2.7 4 Calculator shows this result: 53.1441

Problem: 5.71⁵ ?= Calculator shows this result: 6069.886093

Cube Root Key

Problem: ³√125 = ?

Press these calculator keys: 125 Calculator shows this result: 5

Recall that the cube root ³√125 , asks the question, "what number raised to the third power is 125

³√125 = 5 because 5³ = 5 x5x5 = 125

Problem: ³√25 = ?

Press these calculator keys: 25 Calculator shows this result: 2.924017738

Problem: a) √200 b) ³√200 = ? Results: a) 14.14213562 b) 5.848035476

n√x

Squaring Key

To square a number, that is, raise a number to the second power, or multiply a number by itself, type in the number, then press the key.

Problem: 8² = ?

Press these calculator keys: 8 (Do NOT press the key) Calculator shows this result: 64

Problem: 4.71² = ?

Press these calculator keys: 4.71 Calculator shows this result: 22.1841

Problem: 54.7² = ? Calculator shows this result: 2992.09

Square Root Key

The Square Root Key, , is also a "green" key so you must press the green key first to use the Square Root key. The key is located above the key.

Problem: √144 = ?

Press these calculator keys: 144 Calculator shows this result: 12

Problem: √10 = ?

Press these calculator keys: 10 Calculator shows this result: 3.16227766

Problem: √351 = Calculator shows this result: 18.734994

FIX Key

This is also a "green" key so you have to press the green key to use the key. The key is located in the fourth row and it is above the key. The purpose of the key is to "fix" the number of digits displayed on the calculator’s screen to the right of the decimal point.

If you want the result of your calculations to be rounded to the nearest hundredth automatically by the calculator, use the key as follows:

Press these calculator keys: [ 2 ] Calculator shows this result: All numbers displayed on the screen will be rounded to 2 places to the right of the decimal point (to the nearest hundredth). Press the keys and the number in the display should be 3.14, which is π rounded to the nearest hundredth, in other words, rounded (FIXED) to 2 places to the right of the decimal point.

Problem: Display the results of your calculations rounded to 4 digits to the right of the decimal point: π + 1 = ?

Press these calculator keys: [ 4 ] Calculator shows this result: 3.1416

Problem: Find the square root of 40, √40, and display that answer rounded to the nearest thousandth.

Press these calculator keys: [ 4 ] 40 Calculator shows this result: 6.3246

Problem: Round the results of your calculation with 5 digits to the right of the decimal point: √30 + π Calculator shows this result: 8.61882

NOTE: Press the button to "un-FIX" the OGT calculator.

Factorial Key

5!, which is read, "5 factorial", means (5 times 4 times 3 times 2 times 1), or 5! = 120.

To use the factorial key on the OGT calculator to do the above factorial:

Problem: 5! = ?

Press these calculator keys: 5 Calculator shows this result: 120

Problem: 8! = ?

Press these calculator keys: 8 Calculator shows this result: 40320

Memory Key: X store into Memory , Recall from Memory

The key places the current value that is displayed on the calculator into a memory location called M. That number is stored there until either the number is overwritten by storing a different number into M, or until the - the All Clear button - is pressed. This key is usually used to store intermediate results, that is, numbers that will be used in a later calculation.

Problem: Evaluate: 2.9√5/ π+1 by using the key and not the ( ) keys. Round the answer to the nearest thousandth. Plan: First: evaluate the denominator. Second: store that value into the calculator’s memory (M). Third: Evaluate the numerator. Fourth: Divide the answer from part three (the numerator) by the value stored in Memory (M), which is the denominator.

Press these calculator keys: 1 Notice that an ‘M’ appears in the upper left corner of the display of the calculator. 2.9 5 [ ]

Calculator shows this result: 1.565725477 which rounds to 1.566 to the nearest thousandth.

Problem: Evaluate to the nearest hundredth: 3π - 2.7² / √5+6

Plan: the same plan as we used in the previous example.

Press these calculator keys: 5 [ ] 6 3 2.7

Calculator shows this result: 0.259198681 which rounds to 0.26, to the nearest hundredth.

Problem: Evaluate to the nearest hundredth: π + 7/ 6.4² - ³√30

Calculator shows this result: 0.267922092, which is 0.268 to the nearest thousandth.

NOTE: For extra practice, do the last three examples, but use ( ) instead of the memory keys.

1) Check if you receive identical answers, and

2) Decide which way is easier.

Parentheses Keys

Problem: Simplify: 4.7(6.1 - 8)

NOTE: The OGT calculator does not see ( ) as a command for multiplication. You must press the times key, .

Press these calculator keys: 4.7 6.1 8 Calculator shows this result: -8.93

There are a few other things to notice when you use ( ) keys. When you press the left parenthesis key, , two things occurred:

1) 0 appeared in the display

2) ( ) appeared in the lower right corner of the display

The ( ) appear in that corner until the right parenthesis, , is pressed.

***When using ( ), make sure that you press the key to get the final answer. It is very easy to forget to do that here. Be careful!

Problem: Simplify: 4.85 + 2.97/ 6.85 x 12

Press these calculator keys: 4.85 2.97 6.85 12 Calculator shows this result: 0.095133819

***Be careful -a common wrong answer is 82.2, which is the result before the key is pressed. The key is NEVER the last key pressed!

Problem: Simplify: 6.7 - 10.93/ 48.4 x 1.7 Calculator shows this result: -0.0514098

Problem: Simplify: 12!/ 4! 8!

Press these calculator keys:12 4 8 Calculator shows this result: 495

Problem: Simplify: 11!/ 5! 6! Calculator shows this result: 462

Degrees-Minutes-Seconds Key

The key converts an angle that is measured in decimal degrees, for example, 23.75°, into an angle that is measured in Degrees, Minutes, and Seconds, which is 23° 45' (23 degrees and 45 minutes). You will be asked to write your angle measurements to the nearest degree or tenth of a degree on the Ohio Graduation Test (OGT). We show you how to convert to Degrees, Minutes, and Seconds.

Problem: Rewrite 24.72° in Degrees, Minutes, Seconds.

Press these calculator keys: 24.72 Calculator shows this result: 24° 43' 12 "

Problem: Rewrite 14.523° in Degrees, Minutes, Seconds

Press these calculator keys: 14.523 Calculator shows this result: Calculator displays: 14° 31' 22"8, which actually means 14° 31' 22.8"

Degree Key

Problem: Rewrite 56 ° 17' in decimal degrees rounded to the nearest hundredth of a degree.

Press these calculator keys: 56.17 Calculator shows this result: 56.2833333° or 56.28°

Problem: Rewrite 131° 51’ in decimal degrees rounded to the nearest hundredth of a degree.

Press these calculator keys: 131.51 Calculator shows this result: 131.85°

Problem: Rewrite 23.14° in degrees, minutes, seconds. Calculator shows this result: 23° 08' 24"

Problem: Rewrite 13° 39' in decimal degrees to the nearest hundredth. Calculator shows this result: 13.65°

Trigonometric Function Keys:

When using the trigonometry function keys, we must be in Degree mode. That is what mode the calculator is in when we press the key. So if the word ‘DEG’ does not appear in the display, press the key until it appears.

Problem: You will be given the measure of the angle and asked to compute one of the trigonometric functions for that angle.

For each of the following, calculate and round your final answer to 4 places to the right of the decimal point.

a) sin35^o

Press these calculator keys: 35 Calculator shows this result: 0.573576436, which rounds to 0.5736.

b) cos81^o

Press these calculator keys: 81 Calculator shows this result: 0.156434465, which rounds to 0.1564.

c) tan51^o

Press these calculator keys: 51 Calculator shows this result: 1.234897157, which rounds to 1.2349. Now we will reverse the procedure. That is, you will be supplied with the trigonometric value and ask to find the measure of the angle to the nearest tenth of a degree. To do these types of calculations, we need to use the inverse trigonometric function keys, which are located in green above the regular trigonometry function keys.

Recall that 1sin− is read "the inverse sine of", 1cos− is read "the inverse cosine of", and 1tan− is read "the inverse tangent of." These inverse keys find the value of the missing angles.

Examples. For each of the following, find the value of the missing angles to the nearest tenth of a degree.

a) sinA= 0.4389

Press these calculator keys: 0.4389 Calculator shows this result: 26.03371786, which means that the measure of angle A is approximately 26.0^o, rounded to the nearest tenth of a degree.

b) cosQ= 2/3

Press these calculator keys: 2 3 Calculator shows this result: the measure of angle Q is approximately 48.2^o, to the nearest tenth of a degree. NOTE: you could have also used the fraction key to enter the 2/3. See below: Keystrokes: 2 3 See the result (above).

c) tan E =√5/2

Press these calculator keys: 5 [ ] 2 Calculator shows this result: the measure of angle E is 48.2^o, rounded to the nearest tenth of a degree.

Problem: Compute to 4 decimal places: a) sin53^o b) cos21^o

Results: a) 0.7986 b) 0.9336

Fractions on the OGT Calculator

The key and the green one above it, , are very powerful and popular keys on the OGT calculator ...especially if you would rather avoid doing fraction calculations by hand.

We will investigate how to enter fractions, simplify fractions (rewrite in lowest terms), enter mixed numbers, rewrite mixed numbers as fractions (sometimes called improper fractions), add, subtract, multiply and divide fractions and mixed numbers.

Problem: Simplify: 64/120

Press these calculator keys: 64 120 Calculator shows this result: 8 15 which means 8 15

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