Glossary

Area: The size that a surface takes up, measured in square units.

Bacteria: Any of a large group of one-celled round, spiral or rod-shaped microscopic organisms of various shapes that are often agents of fermentation and putrefaction and that may cause disease.

Chemical change: A change in matter that produces a new substance.

Circumference: The distance around a circle.

Estimation: Judging the approximate value, size or worth of something.

Fractions: When an object is divided into a number of equal parts, then each part is called a fraction.

Front-end rounding or truncating: To truncate means to shorten or cut off. A number that is truncated has all the numbers changed to zero after the number being rounded. For example, if you are truncating to the tens place, 57 = 50 and 422 = 420.

Fungi: Any organism, including mushrooms, yeasts, molds, rusts and others, characterized by lack of chlorophyll and by subsistence on organic matter.

Global Positioning System (GPS): A satellite-based navigation system made up of a network of 24 satellites orbiting the earth.

Length: A measure of how long something is from end to end.

Mass: The amount of matter in an object.

Matter: Something that occupies space (volume) and has weight (mass). There are three states of matter: solid, liquid and gas.

Microorganism or microbe: An organism that is so small that it is microscopic and invisible to the naked eye.

Money: A medium of exchange that comes in a variety of forms. The most common is currency — bills and change. Other forms of money include checks, credit cards, check cards, online banking, etc.

Perimeter: The distance around the outside of a shape.

Physical change: A change in matter where no new substance is produced.

Rounding: A number that has about the same value as the number you start with, but it is less exact.

Temperature: The amount of warmness or coldness in an object.

Thermometer: An instrument used to measure temperatures or temperature changes.

Time: Defined in two ways. 1) A measure of the period between two events, or the period in which something happens. 2) The precise moment determined by a clock.

Truncating or front-end rounding: To truncate means to shorten or cut off. A number that is truncated has all the numbers changed to zero after the number being rounded. For example, if you are truncating to the tens place, 57 = 50 and 422 = 420.

Volume: The amount of space taken up by a three-dimensional object.