Praxis 5003 key terms

The value a digit has because of its position in a number. In 4,703 the 7 stands for 7 hundreds, or 700; moving one place left makes a digit ten times greater.

A whole number greater than 1 whose only factors are 1 and itself, such as 2, 3, 5, 7, and 11. The number 1 is neither prime nor composite.

A whole number greater than 1 that has at least one factor other than 1 and itself, such as 12 = 3 × 4. Every composite number can be written as a product of primes.

The largest whole number that divides two or more numbers evenly. The greatest common factor of 12 and 18 is 6, and it is used to simplify fractions.

The smallest nonzero number that is a multiple of two or more given numbers. The least common multiple of 4 and 6 is 12, the usual choice for a common denominator.

A number that names part of a whole or part of a set, written as a numerator over a denominator. In 3/5 the denominator tells that the whole is split into five equal parts and the numerator that three are taken.

Fractions that have different numerators and denominators but name the same amount, such as 1/2, 2/4, and 5/10. Multiplying or dividing both parts by the same nonzero number produces one.

A way of writing numbers using place value based on tenths, hundredths, thousandths, and so on, marked by a decimal point. For example, 0.75 means seven tenths plus five hundredths.

A ratio that compares a number to 100. Fifty percent means 50 out of every 100, which equals 50/100 or 0.5, so percents convert easily to fractions and decimals.

A comparison of two quantities by division, written as 3 to 4, 3:4, or 3/4. The order matters, because 3:4 and 4:3 describe different comparisons.

A rate in which the second quantity is exactly one unit, such as 65 miles per 1 hour or $2.50 per 1 pound. Dividing to find a unit rate makes rates easier to compare.

Any number in the set of whole numbers and their opposites, including zero: ..., −3, −2, −1, 0, 1, 2, 3, ... Integers never include fractions or decimals.

The distance between a number and zero on the number line, written with vertical bars. Because distance is never negative, |−7| = 7 and |7| = 7.

The agreed sequence for evaluating an expression: grouping symbols first, then exponents, then multiplication and division from left to right, then addition and subtraction from left to right.

A letter or other symbol that stands for a number that is unknown or that can change. In 4n + 1 the variable n may stand for any number.

A mathematical phrase built from numbers, variables, and operations with no equals sign, such as 5x − 8. An expression can be evaluated or simplified but not solved.

A statement that two expressions have the same value, written with an equals sign, such as 3x + 2 = 14. Solving an equation means finding the variable value that makes the statement true.

The number that multiplies a variable in a term. In 7y the coefficient is 7; in −x the coefficient is an understood −1.

A rule that pairs each input value with exactly one output value. Tables, graphs, equations, and verbal rules can all describe the same function.

The rule that a(b + c) = ab + ac. Multiplying a sum by a number gives the same result as multiplying each part and then adding the products.

A relationship in which one quantity is always a constant multiple of the other, so the ratio between them stays the same. Its graph is a straight line through the origin.

A statement that compares two expressions using <, >, ≤, ≥, or ≠, such as x + 3 > 10. Unlike an equation, an inequality usually has a whole range of solutions.

A closed two-dimensional figure formed by straight line segments that meet only at their endpoints. Triangles, quadrilaterals, pentagons, and hexagons are all polygons.

A polygon with exactly four straight sides, such as a square, rectangle, rhombus, trapezoid, or parallelogram. Some of these categories sit inside others; every square is also a rectangle.

Describing figures that have exactly the same shape and size, with matching sides and matching angles. Sliding, turning, or flipping a figure produces an image congruent to it.

Describing figures that have the same shape but not necessarily the same size. Corresponding angles are equal and corresponding side lengths form equal ratios called the scale factor.

The total distance around a closed plane figure, found by adding its side lengths. Perimeter is measured in linear units such as inches, centimeters, or meters.

The number of square units needed to cover a plane figure without gaps or overlaps. A rectangle's area is length times width, measured in square units.

The amount of space a three-dimensional figure occupies, measured in cubic units. For a rectangular prism, volume equals length times width times height.

The flat grid formed by a horizontal x-axis and a vertical y-axis meeting at the origin. Every point on it is named by exactly one ordered pair.

Two numbers written in a fixed order, (x, y), giving a point's horizontal distance from zero and then its vertical distance. Reversing the numbers usually names a different point.

Changing a measurement into a different unit by multiplying by a ratio equal to one, such as 1 yard over 3 feet. Since 1 yard equals 3 feet, 4 yards becomes 12 feet.

The arithmetic average of a data set: add all the values, then divide by how many values there are. The mean is pulled toward outliers more than the median is.

The middle value when the data are listed from least to greatest. With an even number of values, the median is the mean of the two middle ones.

The value that appears most frequently in a data set. A set can have one mode, several modes, or no mode at all.

The difference between the greatest and least values in a data set. Range gives a quick sense of how spread out the data are but ignores the middle values.

A graph that places a number line along the bottom and a mark above a value for each time it occurs. It shows how the data cluster and which values repeat.

The number of favorable outcomes divided by the total number of equally likely outcomes, such as 1/6 for rolling a 3 on a fair number cube. It describes what should happen, not what did.

The number of times an event actually occurs divided by the total number of trials performed. Repeating the experiment usually brings this value closer to the theoretical probability.

The complete set of all possible outcomes of an experiment, such as {1, 2, 3, 4, 5, 6} for rolling one number cube. It is used to count favorable and total outcomes.