Everyday Mathematics Parent Handbook

Glossary for Everyday Mathematics

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scale drawing (4) An accurate picture of an object in which all parts are drawn to the same scale. If an actual object measured 33 yards by 22 yards, a scale drawing of it might measure 33 millimeters by 22 millimeters. scale factor (3) A number that names "how many times as many?" or "what fraction of?" one quantity is of another quantity. scalene triangle (4) A triangle in which no sides are the same length. scientific notation (4) A system for representing numbers in which a number is written as the product of a power of 10 and a number that is at least 1 but less than 10. Scientific notation allows writing big and small numbers with only a few symbols. Example: 4,000,000 in scientific notation is 4 x 106. 0.00001 in scientific notation is 1 x 10-6 scroll (1) A roll of paper with words and/or pictures written on it. semicircle (2) Half of a circle; either of two parts of a circle between (and including) the endpoints of a diameter. significant figures (4) In a count or measurement, digits that reflect the precision of the result: How reliable is the result? How much variation might there be if the count or measurement were repeated? How closely can the measuring instrument measure the object? Significant figures are usually non-zero digits, or 0 when it is between non-zero digits. The distance from the Earth to the Sun is 93,000,000 miles, with two significant digits. similar figures (3) Figures that have the same shape but are not necessarily the same size. skip counting (K) Counting by a specified added amount from a specified starting number For example, skip counting by 2’s from 2, would be 2, 4, 6, 8. . . Skip counting by 10’s from 23 would be 23, 33, 43, 53. . .
sphere (1) The set of all points in space that are a given distance (the radius of the sphere) from a given point (the center of the sphere). A ball is shaped like a sphere, as is the Earth. A hemisphere is "half of a sphere;" that is, either of the two parts into which the sphere is divided by its equator (or by any circle on the sphere with its center at the center of the sphere).
square array (4) A rectangular array with the same number of rows as columns.
square number (2) A number that is the product of a whole number multiplied by itself; a whole number to the second power. 25 is a square number, because 25 = 5 x 5. A square number can be represented by a square array. Example: 352 = 35 x 35 = 1225.
square pyramid (4) A geometric solid consisting of a square base and triangular faces that meet at an apex (point).
square root of a number (4) The square root of a number n is a number which, when multiplied by itself, results in the number n. Example: 4 is a square root of 16, because 4 x 4 = 16. The other square root of 16 is -4 because - 4 x (-4) = 16. square unit (2) A unit used in area measurement. standard notation (4) The most familiar way of representing whole numbers, integers, and decimals by writing digits in specified places. standard unit (1) A uniform unit of measure. subtraction (1) A mathematical operation based on "taking away" or comparing. The number being subtracted is called the subtrahend; the number it is subtracted from is called the minuend; the result of subtraction is called the difference. In 45 - 12 = 33, 45 is the minuend, 12 is the subtrahend, and 33 is the difference. Addition "undoes" subtraction. 45 - 12 = 33 and 45 = 12 + 33. sum (1) The result of adding two or more numbers. symmetry (1) A figure that when divided into two parts has each part the exact mirror image of the other part.
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tally mark (K) Marks used to keep track of data (|||| |||).
tangent (4) Intersecting at exactly one point.
template (1) A pattern used as a guide in making something accurately. tessellation (4) An arrangement of closed shapes that covers a surface completely without overlaps or gaps. tetrahedron (2) A polyhedron with four faces. three dimensional (3-D) (1) Objects with thickness as well as length and width. tiling (3) Covering a surface with uniform shapes so there are no gaps or overlaps, except possibly gaps around the edges.
translation (slide) (4) The motion of an object or picture along a straight line.
transparent mirror (4) A mirror with a front and back face that has a recessed edge used for drawing lines of symmetry.
trapezoid (K) A quadrilateral that has exactly one pair of parallel sides. No two sides need be the same length.
triangle (1) A polygon with three sides.
triangular prism (1) A prism whose base is a triangle.
trillion (4) A digit(s) followed by 12 whole-number places. One trillion written in number form is 1,000,000,000,000 or in exponential form 1012. triple (2) Three times an amount. turn-around facts (1) A pair of facts in which the order of the addends or the factors is reversed. If a fact is known, its turn-around is also known. Example: 3 + 5 = 8 and 5 + 3 = 8 or 3 x 9 = 27 and 9 x 3 = 27. turn (3) Rotation. twin primes (4) Two prime numbers that are separated by just one composite number. Example: 3 and 5 are twin primes, because they are separated by the composite number 4. two-dimensional (2-D) (1) Objects completely within a flat surface; objects with length and width, but no thickness.
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