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Percent
Percents are
like
fractions and
decimals because they count PART of
something.
Whole numbers (0, 1, 2, 3, ...)
count whole things -- like a whole pizza.
You can use a percentages to count part of the pizza.
Half of a pizza would be 50% of a pizza. One-fourth of
a pizza would be 25% of a pizza.
Examples: 20%
0.05%
245.2% |
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Permutations
A permutation is an
arrangement of objects.
Example: How many ways can you arrange the letters
A, B
and C?
6 ways
ABC
ACB
BAC
BCA
CAB
CBA
For more info, check out my
Permutations lesson. |
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Point
A point is a location
in space. I can't even draw you a real picture of a
point, because my dot would really be a blob of points.
It's impossible to really draw just one point. So,
when you're in Algebra and you have to graph points, you'll
just have to pretend. |
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Polyhedron
A polyhedron is a
three-dimensional object whose
faces
are polygons. The most famous set of polyhedra
(that's the plural) is the five Platonic Solids
that may have been discovered by Pythagoras.
These solids are special because they are the only
ones that are made up of regular polygons.
They are the tetrahedron, the
cube (hexahedron),
the octahedron, the
dodecahedron and the
icosahedron.
For more info, check out my
Polyhedra Gallery. |
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Polynomial
For now (and probably
forever), you can just think of a polynomial as a bunch of
blobs that are being added and subtracted. The blobs
are just products of numbers and
variables (letters) with
exponents.
Here's an example:
For more info and more examples, check out my
Polynomial lessons. |
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Positive Numbers
Positive numbers
are those that appear to the right of
zero on the number line.
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Prime
A
number is prime if it has exactly two
factors: 1 and
itself. The number 20
is not a prime number since it has more than two factors:
1, 2, 4, 5, 10, 20. The number 20 is
composite. The number
1 is neither prime nor composite since it only has one
factor: 1.
Here are some prime numbers:
2,
3,
5,
7,
11,
13,
17,
19,
23,
29, ... |
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Prism
A prism is a
polyhedron that is formed with
two parallel polygons (the bases - top and bottom)
that are connected at the
edges with rectangles.
My example in the picture is a right prism since the
sides
form
right (90 degree) angles with the
bases. |
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Probability
A probability tells us
how likely it is for an event to occur. When the
weatherman says there's a 60% chance of rain, that's a
probability. When you toss a coin, there's a 50% (1/2)
probability that "tails" will come up.
Let's look at rolling a die... There are
6 possible rolls (1, 2, 3, 4,
5, 6). This number goes in the
denominator. What if we want to know the
probability for rolling a 5... There is
one 5 on a die... So,
there's one chance
out of
six that we'll roll a 5. That's a
1/6
probability. What if we want to roll an odd number?
There are three odd numbers on
a die (1, 3, 5)... That's three
chances out of
six... That's a
3/6
(or 1/2)
probability. |
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Product
The
product is the
answer when you
multiply two (or more)
numbers.
Example:
3
x 2
=
6
For more info, check out my
Multiplication Lessons. |
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Proof
A proof is an argument
that shows something (like a
theorem) is true beyond any doubt. In
math, sometimes a proof is all numbers and symbols and
sometimes there are sentences too.
There are different kinds of formal proofs in math:
direct proof, indirect proof and mathematical induction, to
name a few. |
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Proportion
A proportion is simply
two
ratios that are equivalent
to each other. Proportions are usually
used in Algebra to solve for some missing
information. |
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Protractor
A protractor is a
device used in Geometry to measure and draw angles. |
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Pythagorean
Identities
The Pythagorean
Identities are
For more info on the Pythagorean Identities and
where they come from, check out my
Pythagorean
Identities lesson. |
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Pythagorean
Triples
Pythagorean triples
are also called Pythagorean numbers. These are whole
numbers that work together in the
Pythagorean theorem.
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