Math: How to convert between fraction and decimal on the Casio fx-991ES PLUS C

Tutoring math, you notice the peculiarities of scientific calculators. The tutor brings up one about the Casio fx-991ES PLUS C.

If you enter the operation 14÷9 into the Casio fx-991ES PLUS C, you’ll just as likely see 14/9 on the screen. If you want the decimal, just press the S⇔D key.

You can keep pressing the S⇔D key to toggle through various formats of the answer.

HTH:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage, math: logs in variable bases with the Casio fx-991ES PLUS C

Tutoring math, you come to appreciate calculators. The tutor points out an interesting feature on the Casio fx-991ES PLUS C.

Typically, the log key on a calculator means “base 10 log”, aka “common log.” What about base 7 log, for instance?

The Casio fx-991ES PLUS C has a log□ key which can accept an input for the base.

Example: On the Casio fx-991ES PLUS C, evaluate log762.

Solution:

  1. Press the log□ key, second down on the right.
  2. Press 7, then arrow over once, then key 62, then arrow out of the brackets.
  3. Press =

Everyone not blessed with the Casio fx-991ES PLUS C can just enter log62/log7 =

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage: the ENG feature on the Casio fx-991ES PLUS C

Tutoring math, calculator features are always topical. The tutor mentions the ENG function on the Casio fx-991ES PLUS C.

Back in my Halloween, 2015 post, I explain the general idea of the ENG function – that engineers and technicians often like to refer to measurements in “thousand” groupings. For instance, 1249W is 1.249kW; 0.067A is 67mA.

Example: convert 0.78A to mA

  1. Key 0.78 = (you must press = for this to work)
  2. Press ENG: hopefully you see 780×10-3

Example: convert 1249W to kW.

Solution: to go up to the bigger unit, use SHIFT ENG, like so:

  1. Key 1249 = (once again, you must press =)
  2. Press SHIFT then ENG. Hopefully you see 1.249×103

HTH:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage: finding final price after discount and tax with the HP-10B

Tutoring financial math, you might often use the HP-10B. The tutor shows how easily it can apply a discount then add tax to get the final price.

Example: Imagine a handbag is regular price $85 but is discounted by 20%. Assuming 12% sales tax, find final price using the HP-10B.

Solution:

  1. Key in 85
  2. Key in – 20 % =
  3. Key in + 12 % =

HTH:)

Source:

Hewlett-Packard HP-10B Business Calculator Owner’s Manual. Corvallis: Hewlett-Packard, 1994.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage: markup on the HP-10B

Tutoring financial math, you might fall in love with a calculator. The tutor tells about markup on the HP-10B.

Example: Imagine you buy a product for $35, then want to apply a 25% markup. Find the tag price using the HP-10B.

Solution:

  1. Key in 35 then CST
  2. Key in 25 then the orange key then MAR
  3. Press PRC

HTH:)

Source:

Hewlett-Packard HP-10B Business Calculator Owner’s Manual. Corvallis: Hewlett-Packard, 1994.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage: memory on the HP-10B

Tutoring financial math, you’ll likely encounter the capable HP-10B. The tutor tells how to use its user-accessible memory.

The HP-10B seems to have 11 dedicated places to store your own numbers. The locations are at 0 to 9, plus there is the M register.

Example: On the HP-10B, store the number 65.21 in register 5.

  1. Key in 65.21
  2. Press the orange key
  3. Press RCL
  4. Press 5

To retrieve the number,

  1. Press RCL
  2. Press 5

HTH:)

Source:

Hewlett-Packard Business Calculator HP-10B Owners Manual. Corvallis: Hewlett-Packard, 1994.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage, statistics: the amazing Casio fx-991ES PLUS C

Tutoring math, you see all kinds of scientific calculators. The tutor continues to praise the Casio fx-991ES PLUS C.

If you were to be marooned on an island with a single calculator…which one would you prefer? The question is absurd, of course. Yet, I believe I know my answer: the Casio fx-991ES PLUS C. It has seemingly endless functionality for a little scientific calculator.

Today I noticed that it calculates binomial pdf.

Example: Using the Casio fx-991ES PLUS C, find the probability of 20 successes in 35 trials when p=0.44.

Solution:

  1. Press MODE, then arrow down
  2. Select 3
  3. Select 4
  4. For a single query, select 2
  5. It will ask for x (the number of successes). Key in 20 =
  6. Next, it will ask for N (the number of trials). Key in 35 =
  7. Now it will ask for p (the probability of success each time). Key in .44 =
  8. Hopefully you receive the answer 0.0401

HTH:)

Source:

Casio fx-991ES PLUS C User’s Guide

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage: converting from rectangular to polar coordinates using the Casio fx-991ES PLUS C

Tutoring math, you encounter the differences between calculators even from the same manufacturer. Now, the tutor shows how to convert from rectangular to polar coordinates using the Casio fx-991ES PLUS C.

In my post from May 18 I show how to convert from rectangular to polar coordinates using the Casio fx-260solar. Here’s how to do the same with the Casio fx-991ES PLUS C:

Example: Convert (-80,-56) to polar coordinates using the Casio fx-991ES PLUS C.

Solution:

Key in SHIFT + -80 SHIFT ) -56 ) =

Across the bottom, the length (r) will show first; arrow over to see θ.

HTH:)

Source:

Casio fx-991ES PLUS C User’s Guide.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage: how to convert rectangular coordinates to polar with the Casio fx-260solar

Tutoring calculus, you cover polar coordinates. The tutor shows how to convert from rectangular to polar coordinates on the Casio fx-260solar.

Example:

Convert the coordinates (-56,12) to polar with the Casio fx-260solar.

Solution:

  1. Key in 56 +/- SHIFT + 12 =
  2. Hopefully you get 57.27, which is the length.
  3. Now key in SHIFT, then the left bracket key.
  4. Hopefully you get 167.9, which is the angle in degrees.

HTH:)

Source:

Casio fx-260solar manual

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Calculator usage: the greatest common divisor (or greatest common factor) function on the Casio fx-991ES PLUS C

Tutoring math, calculator usage is of constant importance. The tutor shows how to get the greatest common divisor on the Casio fx-991ES PLUS C.

Example: Find the GCD of 96 and 60.

Solution:

Key in ALPHA x 96 , 60 ) =

HTH:)

Source:

Casio fx-991ES PLUS C User’s Guide

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.