Cool math .com - Online Math Dictionary

Online Math Dictionary: M
Easy to understand math definitions for K-Algebra mathematics
Just scroll down or click on the word you want and I'll scroll down for you!

magic square	mean	median
midpoint formula	milligram	millimeter
millisecond	minuend	Mobius strip
mode	monomial	multiple
multiplicity

Magic Square
A magic square is filled with the numbers 1-9 (each used once) so that the sum of every row and every column is the same (15 in my example).

Mean
The mean of a group of numbers is the same thing as the average. It's weird to define "average" in words, but really easy to show what it is.
Look at this list of numbers: 3, 6, 13, 4, 9... Add them up and we get 35... Now, divide by how many numbers there are. There are five numbers, so divide 35 by 5... We get 7 and that's the average of this list of numbers. Notice that some of the numbers are above 7 and some are below.

Midpoint Formula
The midpoint of a line segment is the exact point that's in the middle - exactly halfway between the two points. Here's the formula and I've got an example with numbers on the graph on the right:

Given (x1,y1) and (x2,y2) midpoint = ( (x1+x2)/2, (y1+y2)/2)

You don't really need to memorize the formula... Just remember that the midpoint is like the average point... So, you take the average of the x's and the average of the y's.

midoint formula example and graph

Milligram
A milligram is one 1000th of a gram.

Millimeter
A millimeter is one 1000th of a meter.

Millisecond
A millisecond is one 1000th of a second and that's quick, baby!

Minuend
The minuend is the number you are subtracting FROM:
8 - 5 = 3
For more info, check out my Subtraction Lessons.

Mobius Strip
Here's how to make a Mobius stip:
Take a long strip of paper and put the two ends together like you are making a big "0"... Before you tape the two ends together, turn one of them over so that the strip has one twist in it. The cool thing about a Mobius strip is that is just has ONE SIDE!! Huh? How can a piece of paper with two sides make a loop with just one side? Because of the twist! In my pic on the right, one side of my paper was red and the other was purple... Follow your way around and you'll find that you end up where you started, but you'll have gone on the red side and the purple side. Make one yourself and make a long line on it with a pencil and see what happens.

mobius strip

Mode
In a list of numbers (like exam results), the mode is the number that occurs the most.
Example: 4, 5, 7, 8, 9, 4, 5, 4 The mode is 4.

Monomial
A monomial is a polynomial with just one term.
For more info, check out my Polynomial lessons.

Multiple
A multiple is a number that is the product of a given number and some other number.
Examples: 12 is a multiple of 4 (since 4 x 3 = 12).
100 is a multiple of 5 (since 5 x 20 = 100).

Multiplicity
When a root (or zero) occurs more that once in a polynomial, we say that the root has a multiplicity of 2 (if the root occurs twice).
For more info and examples, check out my lesson on Multiplicities.

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