See also the
3D and higher
Browse Elementary School Definitions
Stars indicate particularly interesting answers or
good places to begin browsing.
Selected answers to common questions:
Meters squared or square meters?
Greater than, less than symbols.
- Does 2k4 Mean 2004 or 2400? [01/10/2004]
On internet communities it is common to reduce figures using 'k' as a
shortcut; for example 2k is used instead of 2000. I was under the
impression that a number after the k (such as 2k4) meant 2400, and
that to get 2004 in this system you'd need to write 2k004. But I've
also seen 2k4 used for 2004. Which is correct? Does 2k4 mean 2004 or
- Does a Sphere have Sides? [04/20/2001]
How many sides does a sphere have?
- Do Fractions Have to be Equal? [05/09/2003]
A textbook defines fractions as 'one or more of the equal parts of a
whole.' Is this true? Do the parts of the whole have to be equal?
- Edges vs. Corners [04/18/2002]
My students get confused on how to determine an edge versus a corner,
and counting the number of edges on a geometric figure, say a cube.
- Equable Shapes [04/26/2001]
Is there a rule for how to get equable shapes, that is, shapes with the
same area and perimeter?
- Equals Sign with a Dot or a ~ Over It [01/25/2001]
What does an equals sign with a dot (.) over it mean?
- Equilateral, Isosceles, Scalene - Word Origins [12/09/2001]
I need to find out about the origins of the scalene, isoceles, and
equilateral triangles. How they were named?
- Etymology of the Word 'Quotient' [11/25/2002]
What is the origin of the word 'quotient'?
- Etymology of the Word Rectangle [02/07/2003]
Where does the word 'rectangle' come from?
- Etymology of the Word Rhombus [01/30/2003]
Where does the word rhombus come from?
- Explorations of the Circle [02/09/1999]
What is the definition of a circle? How does it relate to pi? What are
the important parts of a circle?
- Exploring Estimation [08/29/2003]
If a rare truffle is $13.20 for 0.44 oz, estimate the cost of a whole
- Factorials [2/3/1996]
What does 3! mean?
- Factors and Multiples [01/27/1998]
My son is in 4th grade and needs help naming a common multiple of a pair
- Feet per Mile [12/08/1998]
What is the history behind the fact that there are 5,280 feet in a mile?
- Finite Numbers [05/13/2003]
What are finite numbers?
- Flips, Reflections, Rotation, and Quadrants [11/10/1998]
These terms are being used to describe the movement of shapes. What do
they really stand for?
- Further Musings on "Multiplicand" and "Multiplier" [06/09/2011]
A reader shares thoughts on clearer usage of "multiplicand" and "multiplier." Doctor
Peterson responds with some guidelines.
- Greater Than and Less Than Symbols [05/30/2000]
What does it mean when a greater than or less than symbol appears before
a number, with nothing to the left of the symbol?
- Histogram [04/16/2001]
What is a histogram? What makes a histogram good?
- History of the Word [08/21/2006]
Why is a ruler called a ruler?
- 'Honest' Numbers [11/11/2002]
My teacher asked the class: What is the only 'honest' number?
- Interpreting the Difference Between Two Numbers [09/22/2006]
If a question asks "What is the difference between 15 and 12" or "What is the difference between 12 and 15," would your responses be +3 and -3 respectively? Or would they both be +3?
- Intersection of Circles [10/08/1998]
I do not understand the term intersection in geometry.
- Is a Square a Rectangle? [06/04/1997]
Are squares rectangles? What is a pentagon?
- Is a Square a Rhombus? [8/30/1996]
I've come across different definitions of a "rhombus" that make it
unclear whether a square is a rhombus.
- Is Kite the True Name? [03/29/2002]
Is kite the true math name for this shape, or is there another?
- Least Common Multiple with Zero [03/26/2003]
I'm trying to find any reference about the least common multiple of
two numbers when one (or both) is zero.
- Left Angles [06/01/1999]
What is a left angle?
- Leg of a Triangle [04/02/2002]
I need to know where the name "leg" of a triangle comes from, or what its
- Length or Width? [12/02/2003]
Can you please explain the difference between height, length, width
and depth? Is it always the same for each thing?
- Linear Foot [7/1/1996]
How much is a linear foot?
- Line Segments and the Origins of Geometry [6/7/1995]
How can segments be lines? Why is geometry called geometry?
- Line under Greater or Less Than Symbol [01/26/2001]
What does it mean when there is a line under the greater or less than
- Measuring by Degrees [06/16/2002]
Why is it that angles and temperature are both measured in
- Meters Squared vs. Square Meters [11/18/2001]
Is 12 m^2 better read as 12 square meters or 12 meters squared?
- Miles Squared vs. Square Miles [07/09/1999]
What is the difference between 10 square miles and 10 miles square?
- Mnemonic for Less Than and Greater Than [08/11/1999]
What was the old adage for telling how to read the less than and greater
than symbols correctly?
- Moving the Decimal Point [12/04/2002]
When you divide two decimals, what is it called when you move the
- Multiplier, Sum, Difference, Product, Quotient, Dividend [11/25/1997]
What is a multiplier? an addend? a minuend? a product? Why is the number that is being divided the "dividend"?