Everyday Mathematics Parent Handbook

Glossary for Everyday Mathematics

A B C D E F G H I K L M N O P Q R S T U V W X Y Z

A
abundant number (4) A number in which the sum of all its proper factors is greater than the number itself. Example: 12 is an abundant number because the sum of its proper factors is 1 + 2 + 3 + 4 + 6 = 16 and 16 is greater than 12. acre (4) A unit of area. A commonly used measure of land that can be any shape provided it equals 43,560 square feet. acute angle (4) An angle greater than 0 degrees and less than 90 degrees. See angle. addition A mathematical operation based on "putting things together." Numbers being added are called addends; the answer is called the sum. In 12 + 33 = 45, 12 and 33 are addends, and 45 is the sum. Subtraction "undoes" addition: 12 + 33 = 45; 45 - 12 = 33, and 45 - 33 = 12. algorithm (3) A set of step-by-step instructions for doing something — carrying out a computation, solving a problem, and so on. analog clock (1) A clock that shows the time by the positions of the hour and minute hands. A digital clock shows the time as digits in hours and minutes, with a colon separating the two.
angle (1) A figure consisting of two rays with the same endpoint. The endpoint is called the vertex of the angle. An acute angle has a measure greater than 0° and less than 90°. An obtuse angle has a measure-ment greater than 90° and less than 180°. A right angle has a measurement of 90°. A straight angle has a measure of 180°.
angles, adjacent (4) Two angles with a common side, the same vertex, and that do not overlap. In the diagram, angles 1 and 2 are adjacent angles. So are angles 2 and 3, angles 3 and 4, and angles 4 and 1. angles, vertical (4) Two angles with the same vertex, but no sides in common. In the diagram, angles 2 and 4 are vertical angles. They have the same vertex but no sides in common. Their measures are equal. Similarly, angles 1 and 3 are vertical angles.
apex (3) In a pyramid, the point at which all faces except the base meet.
area (2) The measure of the amount of surface inside a closed boundary.
array (K) A rectangular arrangement of objects in rows and columns.
attribute (K) A common feature (size, shape, color, number of parts, and so on) of items in a set. average (mean) (3) A typical or middle value for a set of numbers. It is found by adding the numbers in the set and then dividing the total by the number of values in the set. Example: 2, 4, 5, 9, 10 = 30; 30 ÷ 5 = 6; The mean is 6.
B
bar graph (1) A graph in which horizontal or vertical bars represent data.
base of a polygon (4) The side on which the polygon "sits;" the side that is perpendicular to the height of the polygon.
base of a polyhedron (1) The "bottom" face of a polyhedron; the face whose shape is the basis for classifying a prism or pyramid.
A B C D E F G H I K L M N O P Q R S T U V W X Y Z