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Rename The Greater Than Sign
Shifty Mathematics: Primary school students are taught to use
the phrases greater than and less than in comparing the size or magnitude of
decimals, unsigned numbers. High school students in the discussion of real
numbers have this meaning taken away and replaced by another. This
shift in meaning while comparing signed and unsigned numbers if not noticed,
could be source of confusion. Shifty mathematics terminology is not
recommended.
The mathematical usage of terms or words sometimes drifts away from the
common usage. Here the drift is from the first usage in mathematics and the
common usage. Both coincide.
Two Site
Reviews
- Magellan, the McKinley Internet Directory, 1996:
Mathphobics, this site may ease your fears of the subject, perhaps
even help you enjoy it. The tone of the little lessons and
"appetizers" on math and logic is unintimidating, sometimes
funny and very clear. There are a number of different angles offered,
and you do not need to follow any linear lesson plan. Just pick and
peck. The site also offers some reflections on teaching, so that
teachers can not only use the site as part of their lesson, but also
learn from it. (Magellan is no longer online)
- The
World-Wide Web Virtual Library Education by Country - Canada 1,
2005. Why Slopes: Appetizers and Lessons for Math and Reason. This
online classroom offers appetizers and lessons for math from
arithmetic to calculus or why slopes; for deductive reason (logic) and
critical thinking; and for learning in general. Included here are
opinions on the communication of skills and mathematics instruction.
The logic appetizers are math free. Each appetizer is different. If
one is not to your liking try another. Most are from three books on
understanding and explaining math and reason.
may encourage a visit to site entrance www.whyslopes.com. |
Why Say "More Positive Than" Instead of "Greater Than"
The concept of greater than or more than is understood by
students when dealing with counts or unsigned whole numbers. Before the
introduction of signs, that is negative and positive numbers, finite decimal
expansions extend this idea of greater than or more than. A finite
decimal expansion in particular counts the number of units, tenths, thousandths
and so on that the number it represents can be divided into. Beyond this,
students may be shown or pointed to the comparison of (unsigned) numbers with
infinite decimal expansions.
With the introduction of positive and negative numbers and zero on say the
real number line, the technical ideas of greater than differs from the
common usage, or the introductory idea of comparison of by size or magnitude (apart
from any signs that may be present). Because of this students are tempted to say
that a real number a is greater than another real number b if the
magnitude of a is greater than the magnitude of b. The latter
means real number a is greater in magnitude than another real
number b.
The task is to remove the temptation or conflict. The symbol >
traditional has been called the greater than sign. Technically, given two real
numbers a and b we write a>b if and only if there is
positive number c such that a = b + c. So a is c
units more positive than b.
To avoid confusion, and to align mathematical terminology with the common
usage, the symbol > should be named or renamed the more
positive than symbol on first usage in mathematics. This new name
corresponds precisely to the technical meaning. With this new convention, the
phrase a greater than b can revert to the common usage and mean |a|
> |b|, a comparison of magnitude. Similarly, a < b can be read
not as a is less than b but as a is more negative than b.
This new terminology means there is a positive number c such
that a = b - c or equivalently such that a + c = b. The signs <=
and >= now may be read as more negative or equal to and more
positive or equal to.
Linear and Nonlinear Orderings (optional)
A number b is said to between two other numbers a and c
if and only if there is a positive number q < 1 such that b=qa +
(1-q)c.
Ordering of the real line by the relationship more positive than provides
a linear ordering of the real line: for any three points a, b and c
on the real line the relationships a < b <c imply that b is
between a and c.
Ordering by magnitude provides a linear ordering of the positive numbers. For
any three unsigned (positive) numbers a, b and c, the
relationship a < b < c implies that b is between a
and c. But for any three points a, b and c on the
real line the relationship |a| < |b| < |c| does not imply that b
is between a and c. So ordering by magnitude (or absolute value)
of points on the whole real line is nonlinear.
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Professor Whyslopes:
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Site value lies in the difference
between its ideas and yours.
-
If one site explanation is not to
your liking, try another. Each one is different.
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Two gaps
- The Old Algebra Gap: Algebra
appears with too few words of explanation in high school and college
mathematics. Online Volumes 2 and 3 offer remedies.
Chapters
8 to 12 in Volume 2 put more words into the explanation and
comprehension of algebra. Chapter
14 in Volume 2 with its explicit discussion of the direct and
indirect use a formulas identifies a unifying theme for mathematics
and logic - all rules and patterns will be used forward and backwards.
Chapters
2 to 6 and 12 to 18 in Volume 3 may further ease or avoid the very
challenging use of algebra in the high level mathematics: calculus.
Calculus requires earlier high school mathematics at full strength: (i)
This logically complete but long lesson on complex
numbers shows how to simplify the senior high school
exposition of circular trig functions upto to formulas in the plane
for vectors dot and cross-products. The lesson provides the
route that would have been taken in course design if the key element
of the lesson, a December 2009 invention, had been available in
the 1950s. For further algebra skill development. See the site
coverage of fraction
with units, proportionality,
ratios and rates,
polynomials, quadratics
functions
and straight
line slopes and equations.
- The Arithmetic Gap: An exact and efficient
mastery of arithmetic with decimals and fractions is best (required)
for the high level study of mathematics alone and in science,
technology and business. Pages here on arithmetic
with decimals and integers, on fractions
and solving
linear equations with fractional
operations on stick diagrams may help fill the gap. That
exact and efficient command should be obtained in the last years of
primary school and the first years of secondary school.
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Skill mastery in
mathematics has to be seen to believed. To that end,
learn or teach how-to write and draw the steps in mathematical
figuring or reasoning clearly. Do not try to save space
by doing a sequence of step in one place. Instead, do or record the
steps in sequence on a separate lines to make each step obvious and
verifiable.
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Odds & Ends
Group I
1. Hints for Exams 2A. Exact Arithmetic 2B. Fractions Briefly 3. What is a Variable? 4.. Square Roots 5. Straight Lines 6. Problem Solving Methods 8. Complex No. Applet 7. Trig and Complex No. 9. History of No.s 10. ln(x) and exp(x) 13. Rename the > Sign 14. Problems: Quadratics 15. Problems: Algebra Test 16. Problems: Linear Eqns I 17. Problems: Linear Eqns II 18. Problem Solving Hints 20. Independent Variables 21. Why Logic 22. Why Math 23. The 15 Times Table 24. The 20 Times Table 25. Algebra Formulas 26. On Learning Maths 27. Biology - Growth & Decay 28. Navigation +Time 29 Quibble-What is Algebra 30. Logic in Maths 31. Real Number Operations Learn More
Group II
Constant Retirement Rate Road Safety 3 Strikes Law in California. Math HOW-TOs 9 Steps in Maths Two Gaps
[ Back ] [ Up ] [ Next ]
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For
Senior
High School & Calculus Students
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Words to clearly
introduce algebra and variables
have been missing in course design. For people who cannot do
algebra,
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the missing words may
explain or ease their difficulties. Volume 2 ,Three
Skills for Algebra, in Chapters
8 to 14 & 18 etc, puts words before symbols to
providing the missing words in a way that enrich the
comprehension of all. Those words form the middle part of a algebra
(and logic) lessons aimed at helping or improving all
of high school mathematics and also calculus course
design & delivery.
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For Avid Readers in School & Out -
Online Books
1. Elements of
Reason. 1996
1A. Pattern
Based Reason 1995
1B. Math
Curriculum Notes 1996
2. Three
Skills for Algebra 1995
3.Why
Slopes & More.Math
1995
Tour their forewords.
Calculus Prep or Help: See Volumes 2 & 3,
and this bigger
Calculus
Guide. If your
calculus questions is not answered here, submit
it. Over time, that may complete the site development of
calculus.
For Parents: Speaking
Skills, Reading
& Writing,
Preparing for Science, ends,
values and methods for work and study, parent- friendly maths
skill development booklets for ages 4-14.
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Mostly
For High
School
Intro to Solving
Linear Equations
- a different paths for junior and even senior high
school students. Question for Tutors: When do
you use and when you skip the stick diagram method
here?
Fraction
Skills, thought-based development, Ages 10 to 14 may need a
tutor. Students who have to understand in order
to do may like the development in all or part.
For Senior
High School Mathematics & Calculus
5
wordy Logic
Chapters
4 curious Algebra
Chapters
Words before & besides symbols. A Key Algebra
forward & backwards Chapter
First Calculus
Preview (1st intro)
Four Calculus
Chapters
(2nd intro)
Intro to Complex
Numbers (long)
Intro to Mathematical
Induction (romantic & wordy at first)
Tutors & Instructors:
These lessons introduce skills differently Would you
recommend them?
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More Topics
1. Decimal
Arithmetic Reference!
2. Integers
- Intro to Signed No.s
3. Fractions
- fully explained.
4. Fractions
with Units
5. Number
Theory,
6. Solving
Linear Equations
7 Formulas
for- & backwards -
8. Proportionality,
Back- & For-wards.
9. Logic
Chapters:
10. Euclidean-Geometry
11. Slopes
& Equations of Straight Lines. (Take
I. See take II below)
12. Why
Study Slopes.
13. Maps,
Plans, Similarity & Trig,
(Take II included here)
14. Quadratics:
Starter lessons
15. Polynomials:
Starter lessons
16 Why
Factor Polynomials:
17 Functions
- Forwards & Backwards.
18. Exponents,
Radicals & logs.
19. Complex
Numbers before trig (new advance/ starter lesson)
20. DC
Electric
Circuits Etc
21. Real
Analysis
22. The
Olde Complex No, Trig
& Vector Section.
23. More
Calculus Stuff
- written after Volumes 2 and 3.
Level I Material: New Stuff
Time and Date Matters
Level I Arithmetic.
Money Matters
Measurement Matters
Matters of Chance (Risk Control)
Logic
Chapters
(leave what's not clear in Level I to Level II)
Using/Making Maps and Plans.
(A variant of
Maps,
Plans, Similarity & Trig, to
appear here).
For Instructors
-
Education
Essays
(opinions,
possibilities, references)
- Free
Advice and Directions for teaching primary & high school maths
will be given in online meeting place with voice &
whiteboard.
- Math & Logic How-TOs
1. Arithmetic
2. Algebra
3. More Algebra
4. Beginner Geometry
5. More Geometry
6. Calculus
7. Show Work or Logic
These may be too dense for students. Offering ideas to change
education makes this site different. Nothing
ventured, nothing gained. Site material is
mathematically correct, and where not, please report
errors. The two level program POMME in the site
entrance implies multiple paths for instruction. Supporting
those paths in turn implies a clear destination for
site development and perhaps a new name.
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