Tag Archives: math

#StudyAid for Understanding #Graphs in #Business and #Economics

20 Mar

Quick tip for my students of #Economics#Business, and #Finance — I know some of you have a hard time with the graphs. So many lines gets a little confusing.  If you are a little more “artist” than you are “mathematician” by nature, this is a tip I’ve shared with many students to help them keep track of information.  Buy a DRAWING book, not a notebook with lines on the paper. A blank book. Also buy a set of markers or colored pens.  Pick a color for each “key” thing — For example, Profit can be blue and Revenue can be red.  Draw the graphs in your notebook with those colors. Use the same colors to take notes. Whenever you are writing about “Revenue,” use the red pen. Whenever you are writing about “Profit” use the blue pen.  People who are visual can often see things better when there are different colors. It is easier to avoid getting confused and to keep things clear in your mind.  The students who try this method say it helps them a lot more. It’s worth a try! 

Break Even


#Math – I Shall Rule You!

23 Jan

Math and I are becoming Good friends for the GMAT 😓😭💪 It’s a lengthy process 😜😄

Multiplication Table Practice

7 Jan


If you are looking for a place to practice your multiplication tables (i.e. for ACT, SAT, GRE, GMAT) you can check out the class I made on Quizlet.  You can find the link here.

Divisibility (for GMAT)

6 Jan

Multiplication Table.jpg

For student studying for GMAT or GRE — these are the rules for divisibility (can you divide X by __). 

  • 1 -> All Numbers
  • 2 -> Last digit is divisible by 2
    • (168 is divisible by 2 because the last digit “8” is divisible by 2)
  • 3 -> Sum of Digits is divisible by 3
    • (39 is divisible by 3 because 3+ 9 = 12 which is divisible by 3)
  • 4 -> Last 2 digits are divisible by 4
    • (236 is divisible by 4 because 36 is divisible by 4)
  • 5 -> All Numbers ending in 0 or 5.
  • 6 -> All numbers that are divisible by BOTH 2 and 3.
    • (72 is divisible by 6 because it is divisible by 2 (2/2=1) and divisible by 3 (7+2=9 which is divisible by 3))
  • 7 -> Sum of first digits – (last digit x 2) = number divisible by 7
    • (133 is divisible by 7 because 13 – (3×2) = 13-6 = 7 which is divisible by 7)
  • 8 -> Last 3 digits are divisible by 8
    • (1152 is divisible by 8 because 152 is divisible by 8)
  • 9 -> Sum of all digits is divisible by 9
    • (1458 is divisible by 9 because 1 + 4 + 5 + 8 = 18 which is divisible by 9)
  • 10 -> Ends in 0

Understanding Simple Interest

6 Jun

As always, this lesson is not intended to be professional advice. This is simply lesson material for ESL students in a Managerial Economics and Corporate Finance class. Posted here for their use or for helping other students.

Corporate Value (值)

Financial officers and Managers are extremely responsible for the monetary (货币) goings-on in their companies. As we said before, the Wealth Maximization Rule means that Financial and Corporate Managers are required to maximize (最大化) the profits (收益) for their investors (投资者). 

However, maximizing profits requires in-depth (深入)planning and micro-managing (微观) your funds today while considering (考虑) future profits as well.

There are two types of Value (值) that you should be aware of in Finance and Economics.

The first is called Present Value (现值) and is the value today of something that will increase in value in the future. ExampleWhen we loan someone $1,000 at 10% interest, we know that our $1,000 loan will increase in value in the future.  Present Value = PV.

The second is called Future Value (未来价值) and is the value that the item will have in the future. Future Value = FV.

Interest (利)

I’ll make another post later discussing the many ways to use Present and Future value in your company, but today I just wanted to talk about using them to calculate (计算) “Simple Interest” (单利).  

Usually, when we loan money to someone or invest (投资) our money in something, we do so on the condition that we receive back more money than we put in.  Our corporation is not a charity (慈善机构), we don’t loan you things for free!  The original money we invest is called the Principal (本息).  The extra money we get on top is called the Interest (利).  

Example ~ Company A (a large global corporation) invests $100,000 in a small new business called Company B.  Company B has 10 years to pay it back. But Company A doesn’t do this for free ~ they want to maximize their profits too. That means they have to make some money on this contract (合同).  So they ask Company B to pay an additional 7% per year.   

$100,000 = Principal
7% = Interest


Problem! ~ 7% of what?  
Answer! ~ It depends 🙂   It depends on how Company A decides to count it.

There are two separate mathematical formulas (数学公式) you can use to figure out the Interest.  The first one is called Simple Interest (单利). Simple Interest says that each payment period Company B is going to pay an additional 7% of the original principal ($100,000).  The formula for Simple Interest is:

I = Interest
P = Present Value
R = Interest Rate
T = Number of Years Involved


Company A (a large global corporation) invests $100,000 in a small new business called Company B.  Company B has 10 years to pay it back. The interest rate is 7% per year.   What is the Total Interest (利) you will pay over 10 Years?


The total interest is of course important to both Company A and Company B, there are two other important numbers that the financial managers of Company A want to know–the Present Value of their money and the Future Value of their money.  

Future Value

FV = Future Value (how much money you will make in total)
PV = Present Value

R = Interest Rate
T = Number of years involved

Using our example above with Company A & B, the Future Value is calculated like this:

That means Company A will make a total of $70,000 if they invest their $100,000 in Company B now. Over 10 years, their $100,000 will change into $170,000. 🙂 We like this plan!

Present Value

Sometimes, for example with bonds (债券), we know the Future Value (how much money will be paid to us in the end). But we don’t know how much money has to be invested (Present Value) to get that future result.  So Present Value is calculated by the formula: 

PV = Present Value 
PV = Future Value

R = Interest Rate
T = Number of years involved

Example: Mary Jane knows that in 4 years, she needs to have a total of $150,000 to pay her college tuition. She has an interest-generating account that gives her a 4% interest rate on everything she puts in. How much money should she invest today (Present Value) in order to have $150,000 in 4 years?

That means that Mary Jane needs to put $129,310.35 in her bank account now in order to get $150,000 in the future. 



  1. Value (值)
  2. Present Value (现值)
  3. Future Value (未来价值)
  4. Interest (利)
  5. Simple Interest (单利)
  6. Principal (本息)


Simple Interest

Future Value

Present Value

How to Use Mathematical Equations in your Blogging

27 Apr


If you’re like me, you might need the help of mathematical equations in your blogging or professional writing.  But writings and copying an equation from Word into your website simply won’t work.

Research kept taking me to sites that recommended MathJax, LaTeX, MathML, etc. But to be honest, without an idea of how those work it just got all sorts of confusing. Certainly not as simple as I needed.

But I did finally find a website that worked for me! I’ve tested this method and it allowed me to add Mathematical Equations to:

  1. WordPress
  2. Weebly
  3. LinkedIn

I’m sure it works for other sites as well!

  1. Open up your post. 
  2. On another tab, open up the LaTeX Equation Editor (https://www.codecogs.com/latex/eqneditor.php)
  3. Using the Equation Editor, create your Math Equation.  If you don’t immediately see your format, try hovering your mouse over one of the categories to see more equation formats.
    1. For WordPress: Simply copy the image that the Editor produces and paste into your WordPress post!
    2. For LinkedIn or Weeble: Right click on the image and save it as a GIF. Then go to your post, add an image, and upload the picture.
    3. For other websites where steps 1 or 2 don’t work, you can copy the code at the bottom of the page and paste it into your post via HTML coding.

So Easy!



I Could Have Used This in Calc Classes :(

30 Mar


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