(www.whyslopes.com)
Appetizers and Lessons for Mathematics and Reason 
A calculus and calculus preparation 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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||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.

Slopes and Velocity

Distance Versus Time

Signed Distance along a Road

Suppose in traveling along a road, position at time t is given say by d = f(t). The coordinate d gives a signed distance to the origin or point of reference. Assume positions on one side of this origin have a positive d-coordinate and the positions on the other side of this origin have a negative d coordinate. The absolute value or magnitude of d, that is |d|, gives the unsigned distance to the origin or point of reference. The coordinate d will just be called the distance or signed distance hereafter.

 

Varying Velocity Example

Problem:   Graph the distance d to the origin of a path versus time t for the following journey of Harry Snail.

  1. At two o'clock in the afternoon, he is 50 km west of the origin, he travels further west at 100 km/hr. He drives at this speed for 1[1/2] hours.
  2. At half past three in the afternoon, he stops for one-half hour.
  3. He then drives eastward at 75 km/hr for the next two hours and then stops for another 2 hours.
No other information is available. Also find the slope for each portion of the journey.

Solution.

The trip has five segments. Comments on each segment or portion follow.

1. Before his trip begins, he could be stationary, that is, not moving. This possibility, a suspicion which cannot be confirmed, is represented by the horizontal dashed line. The slope of this speculative dashed line is
m = 0 km
2hr
= 0
So his slope or speed m is 0 or 0 km/hr, as you like. The dashed line in the above diagram could have and probably should have been left out. 

Footnote: When in doubt leave out, is a rule to follow in solutions of problems. Or, when in doubt say so, to show what is certain and what is not. Your credibility is at stake. Indicating precisely where you are guessing in a solution, identifies a question to be answered later by yourself or your instructor. And in marking assignments or tests, I would be less severe with mistakes explicitly identified as guesses than I would be with guesses deceptively presented as sure knowledge. Caution: Not all instructors will have this opinion.

2. The first described portion of the trip starts at the point A = (2 hrs,50km). He reaches the point B = ([3½] hr, 200km) after traveling at 100 kilometer per hour for one and a half hours. The slope of this portion of the trip m = 100[ km/hr] = 100 km per hour.

3. The second described portion of the trip lasts for one half hour. By remaining stopped (stationary) for [1/2] hour, his (t,d) coordinate changes from B = (3[1/2]hr,200km) to C = (4hr,200km). The slope or speed m here is again zero.

4. By traveling at 75 kilometers per hour back towards the origin for two hours, his position coordinates (t,d) change from C = (4hr,200km) to D = (6hr,50km). The slope
m = rise
run
= -75 km
     hr
= -75 km
hr

5. Finally, he does not move for 2 hours. This gives the last portion of the graph with d = 50km and slope m = 0.


 

www.whyslopes.com
Fractions, Ratios, Units, Rates & Proportionality

Fraction Starter Lesson
(simplify, multiply, divide & then add or subtract)

An Alternative Starter Lesson 
(take your pick, or try both)


Area Map & Intro
Fraction Starter Lesson A
Fraction Starter Lesson B
1 What is a Fraction
2  Multiplication I
3 Multiplication II
4 Multiplication III
5 Equivalent Fractions
6. Mixed Numbers
7  Comparison
8  Addition I
9 Addition II
10 Addition III
11  Multiplication IV
12  Division
13 Two Term Ratios
14 Implied Ratios
15  Multiple Ratios
16  Units in Arithmetic
16 Longer Explanation
16 Change Units
16 Products of Quantities
16. Fractions with Units
16. Division+Reciprocals
17 Proportionality
17 Examples
18 Rates & Slopes EGs
18 Constant Rate
18 Varying Rate
18 Velocity Calc., EGs
18 Changing Units
18 Slopes and Units
18 Slopes, No Units
19 RealPlayer Videos
Links

Arithmetic Videos - Real Player Format

Decimal Addition
Methods
Decimal Subtraction Methods
Decimal Multiplication Methods
Decimal Division
Methods


Fractions
Primes
Greatest Common
Divisors

Least Common Multiples

Square Root
Simplification


Area Content Summary

  1. Fraction Starter Lesson
  2. Real Player Videos on Operations with Primes and Fractions
  3. Continuous Ruler & Line Segment
    model for fractions and operations on fractions - Number Theory Area points to the general model.
  4. Distinction between Ratios and Fractions, a nuance: While binary ratios a:b may be identified with a fraction, triple ratios a:b:c and further multiple ratios cannot.
  5. Saying how to add and subtract like monomials in units and their powers, and saying how multiply and divide like and unlike monomials leads to fraction like expressions involving units and a framework for discussion rates - ratios of quantities - a framework for handling proportionality constants, and framework for carrying units through calculation in quantitative disciplines

Hint: See site area on solving linear equations to strengthen fraction sense and algebra skills together. Good luck.


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