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Appetizers and Lessons for Mathematics and Reason 
a calculus and preparation for calculus website, etc.

Online Volumes (Book Orders)
1,  Elements of Reason.
1A. Pattern Based Reason 
1B. Math Curriculum Notes
2. Three Skills for Algebra
3. Why Slopes & More Math

Mathematics Course Designers: LAMP offers food for thought.
More Site Areas 
1. Help Your Child or Teen Learn 
2. Solving Linear Equations
3. Fractions Ratios Rates Proportions & Units
4. Euclidean Geometry
5. Analytic Geometry/Functions 
6. Number Theory
7. More Calculus
More Site Areas 
8. Complex Numbers 
9. Qc Maths  Education  
10. Secondary IV(?) maths
11. Real  Analysis 
12. LaTeX2HotEqn:
13. Electric Circuits Etc  
14.  Français
15. Algebra, Odds & Ends, Etc
More Site Areas 
16. Math Education Essays
17. Telling & Working with Time
18. Maps, Plans & Drawings
19. Quantitative Skills for  home, shopping and work 
20. Statistics Useful, or Not.
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to work online with others.

||Définition d'une variable || Algèbre || Arithmetique || Logique ||La raison basée sur les règles et modelés||
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YOU are better than YOU think. Show yourself  how:  

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Read  logic chapters 1 to 5  in online volume Three Skills for Algebra  for greater skills & confidence in  work 
and study.

Learn to read notes and textbooks like a lawyer, so that no nuance, no subtlety and no clause escapes your attention.

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 Logic chapters 1 to 5  re- appear not in sequence, as is or longer,  in  Volume 1A,  Pattern Based Reason, Bon Appetite.

Logic Mastery
 Amazing, Amusing, Amorous,  Delicious, Delightful, Edifying, Strengthening Elixir. 
It eases work & learning difficulties Makes the hard easier. Opens eyes. Leads to greater precision.
in reading and
writing

Logic mastery makes the hard, easier. Logic mastery  leads to better, stronger and richer comprehension.  Logic mastery  improves reading and writing.  Logic mastery ease learning difficulties.  Logic mastery gives a headstart.  In sum, logic mastery  will develops critical thinking, improve reading and writing, and give a firmer base for work and studies at many levels. Good luck.


After logic  (a) continue reading Three Skills for Algebra, chapters 8 to 14  and do so alongside site area on solving liinear Equations ; or (b) see this calculus starter lesson and Volume 3, Why Slopes  & More Math, chapters 2 to 6;

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Caution: Site advice is approximately correct, for some circumstances, not all. That leaves room for thought

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What may be learnt and when depends on how skills and concepts are developed. Making the hard easier and clearer will allow earlier & richer development of skills and concepts.


Try the Twiddla Whiteboard. In principle, it  allows to people to draw and chat together online on a copy of this webpage or a clean sheet. The chat may be via text or audio.  Visit www.twiddla.com to set up whiteboards to work with the webpage of your choice.

For online automated help in senior high school maths & calculus, visit  quickmath.com  For Automatic Calculus and Algebra Help with derivatives, integrals, graphs, linear equations, matrix algebra, visit calc101.com  With  overlap, each site quickmath & calc101offers a different range of services, some free, some not, all based on webmathematica. Good luck.

Chapter 14 
Compound Interest Calculations
(Compound Growth Calculations)

Previous: Chapter Entrance

2  The Compound Interest Formula

The compound interest formula describes the total amount (including the initial amount) which you find in your bank account when all interest earned is put back (reinvested) to earn further interest, rather than being sent to you or being put aside - provided the interest rate is constant.

When you place an initial amount P into an account, it is called the principal. In a compound interest account the following happens. The money in your account grows to an amount A after n periods. (The number n here identifies the number of periods your money stays in the account without any withdrawals, or deposits, except for interest payments at the end of each period.) The amount A is given by the compound interest formula
A = P(1+i)n
In this formula, the interest rate per period is given by the quantity i. The formula should only be used when interest is compounded. Again, compounded means the interest is reinvested at the end of each period with no other deposits or withdrawals, Each interest payment deposited in your account then earns interest (rent from the bank) in the following periods.

Here is a numerical examples with  i = 5% and P = 1000 to show  how or why the formula works. Observe how the amount at the end of a period is the same as the amount at the start of the next period.

Period
n
Amount at
Start of Period
Amount of Interest Amount at end of Period 103(1.05)n
1 1000.00 50.00 1050.00 1050.00
2 1050.00 52.50 1102.50  
3 1102.50      
4        
5        
  Observe how the amout at the end of a period is equals 100% of  the initial amount plus 5% of the initial amount. So the amount at the end each period is 105% of 1.05 times the initial amount.
Fill in this table with the aid of a calculator to the nearest penny (two decimal places). Observe the formula use shortens the calculation. Note how the amount at the end of one period becomes the amount at the start of the next.  If you do not like to work with interest calculations, turn this whole chapter into a compound population growth model using the values of  A = P(1+i)n to nearest whole number as an approximation to the whole number of individuals present in the population.

The compound interest formula gives an example of a calculation described in algebraic shorthand notation. To use the compound interest formula someone has to explain or show to you the role of each piece of the shorthand. That is done next.

The final compounded amount A on the left-hand side of the compound interest formula can be computed when three numbers are given, namely

  1. the initial amount, also called the principal P,
  2. the interest rate i, and
  3. the number n of compounding periods, possibly months, in which interest is compounded.
When these numbers or quantities are not given, we can only talk or write about compound interest calculations and not do them. Examples in which calculations are done and numbers appear are given below.
  • Other people thinking perhaps of the word rate rather than the word interest in the phrase interest rate, use the letter r instead of i. The shorthand selected does not matter. Like a play, only the plot is important. The actors or letters can be changed.

We could try to describe the compound interest calculation in words alone. This description might be a good essay assignment in a language course alongside the essay of describing in words alone how to tie a shoelace. The task is formidable. The task should persuade you that the algebraic shorthand notation has a few space-saving advantages, even if it may be difficult to read aloud in an understandable way. Formulas like pictures need to be seen to be fully appreciated. Often, mathematics is better written and not spoken.


Examples of how to use the formula directly and indirectly follow. Try to understand both the numerical (arithmetic) and algebraic solutions.

More Chapter Sections: Up ] [ 14 The Formula ] 14. Direct Use - First Example ] 14. Direct Use, Second Example ] 14 Indirect Use - First Example I ] 14 Indirect Use - Second Example ] 14 Going Further ]

 

www.whyslopes.com
2. Three Skills for Algebra 

Foreword, Chapters 
& Appendices 

Foreword
1. Introduction
2. Implication Rules
3. Chains of Reason
4. Romeo and Juliet
4. Induction Mathematical
5 Knowledge Islands
6  Old Language
7  Arith Skill Check
7. The Next Chapters
8 The Three Skills
8 VNR-Concise-Encyclopedia
PS. What is a Variable
9. Algebra Talk
10 Two More Skills
11 Why Shorthand
12 Shorthand Usage
13 What's Next
14 Compound Interest
15 Linear Equations
PS I.  Distributive Law
PS II. Polynomials
16 Painless Proofs
17 Pythagoras
18 Rules of Algebra
19  Functions & Sets
20 Degrees & Radians
21 What's Next
22. Arith & Geometric Sums
23 Summation Notation
24 Your Money
25 Induction & Recursion
26 What's Next
27 Pronouns in Logic
28 Occurrence Tables
29 Contrapositive
30 Truth Tables
31 Indirect Reason
A. Advice For Learning

Real Player Videos

Perfect arithmetic skills with whole numbers & fractions
after or besides chapters 1 to 14.

Arithmetic Videos Summary
Addition with Decimals
Subtraction with Decimals
Multiplication with Decimals
Fraction Arithmetic
Recognizing Primes
Long Division for Decimals
Square Root Simplification
Greatest Common Divisors
Least Common Multiples

Words Before Symbols: 
What is a Variable?
Introduction
Variation between Examples

Variation of Letters

A letter denotes a variable

Cases of Double Variation

Three Notions of a Variable

Constants, Parameters
& Variables

Talking about numbers
Dependent or Independent
Variable, a Matter of Choice

Complex number: starter lesson  

Solving Linear Equations:

A. Letters and Lengths

B. & C. Solving Linear Eq'ns
with stick diagrams.

(i) x + 20 = 29
(ii) 2x + 5 = 20
(iii) 3x + 10 = 32
(iv) 5a + 16 = 3a+ 24

(v)  (½)x + 8 = 24½
(vI)  (¾)a + 16 = (¼)a+ 24
(vii) (¾)q + 17 = 32
(viii) 13 =[2/3]x +7 twice
(x) Animated Examples
(i) Integral Coefficients (A)
(ii) Integral Coefficients (B)
(iii) Fractional Coefficients

(iv) With Parameters

Problem Solving with Linear
Equations in one or many
unknowns, and in essentially 
one unknown - Symbols before
words. 


C. Solving Linear Eq'ns 
without
Stick Diagrams

D. Problems in 
essentially one unknown

E: 2D Systems - Sub Methods.
F. Larger Systems



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