Elementary Algebra

# Key Terms

Elementary AlgebraKey Terms

### Key Terms

absolute value
The absolute value of a number is its distance from 0 on the number line. The absolute value of a number $nn$ is written as $|n||n|$.
The additive identity is the number 0; adding 0 to any number does not change its value.
The opposite of a number is its additive inverse. A number and it additive inverse add to 0.
coefficient
The coefficient of a term is the constant that multiplies the variable in a term.
complex fraction
A complex fraction is a fraction in which the numerator or the denominator contains a fraction.
composite number
A composite number is a counting number that is not prime. A composite number has factors other than 1 and itself.
constant
A constant is a number whose value always stays the same.
counting numbers
The counting numbers are the numbers 1, 2, 3, …
decimal
A decimal is another way of writing a fraction whose denominator is a power of ten.
denominator
The denominator is the value on the bottom part of the fraction that indicates the number of equal parts into which the whole has been divided.
divisible by a number
If a number $mm$ is a multiple of $nn$, then $mm$ is divisible by $nn$. (If 6 is a multiple of 3, then 6 is divisible by 3.)
equality symbol
The symbol “$==$” is called the equal sign. We read $a=ba=b$ as “$aa$ is equal to $bb$.”
equation
An equation is two expressions connected by an equal sign.
equivalent decimals
Two decimals are equivalent if they convert to equivalent fractions.
equivalent fractions
Equivalent fractions are fractions that have the same value.
evaluate an expression
To evaluate an expression means to find the value of the expression when the variable is replaced by a given number.
expression
An expression is a number, a variable, or a combination of numbers and variables using operation symbols.
factors
If $a·b=ma·b=m$, then $aandbaandb$ are factors of $mm$. Since 3 · 4 = 12, then 3 and 4 are factors of 12.
fraction
A fraction is written $abab$, where $b≠0b≠0$ $aa$ is the numerator and $bb$ is the denominator. A fraction represents parts of a whole. The denominator $bb$ is the number of equal parts the whole has been divided into, and the numerator $aa$ indicates how many parts are included.
integers
The whole numbers and their opposites are called the integers: ...−3, −2, −1, 0, 1, 2, 3...
irrational number
An irrational number is a number that cannot be written as the ratio of two integers. Its decimal form does not stop and does not repeat.
least common denominator
The least common denominator (LCD) of two fractions is the Least common multiple (LCM) of their denominators.
least common multiple
The least common multiple of two numbers is the smallest number that is a multiple of both numbers.
like terms
Terms that are either constants or have the same variables raised to the same powers are called like terms.
multiple of a number
A number is a multiple of n if it is the product of a counting number and n.
multiplicative identity
The multiplicative identity is the number 1; multiplying 1 by any number does not change the value of the number.
multiplicative inverse
The reciprocal of a number is its multiplicative inverse. A number and its multiplicative inverse multiply to one.
number line
A number line is used to visualize numbers. The numbers on the number line get larger as they go from left to right, and smaller as they go from right to left.
numerator
The numerator is the value on the top part of the fraction that indicates how many parts of the whole are included.
opposite
The opposite of a number is the number that is the same distance from zero on the number line but on the opposite side of zero: $−a−a$ means the opposite of the number. The notation $−a−a$ is read “the opposite of $aa$.”
origin
The origin is the point labeled 0 on a number line.
percent
A percent is a ratio whose denominator is 100.
prime factorization
The prime factorization of a number is the product of prime numbers that equals the number.
prime number
A prime number is a counting number greater than 1, whose only factors are 1 and itself.
A radical sign is the symbol $mm$ that denotes the positive square root.
rational number
A rational number is a number of the form $pqpq$, where p and q are integers and $q≠0q≠0$. A rational number can be written as the ratio of two integers. Its decimal form stops or repeats.
real number
A real number is a number that is either rational or irrational.
reciprocal
The reciprocal of $abab$ is $baba$. A number and its reciprocal multiply to one: $ab·ba=1ab·ba=1$.
repeating decimal
A repeating decimal is a decimal in which the last digit or group of digits repeats endlessly.
simplified fraction
A fraction is considered simplified if there are no common factors in its numerator and denominator.
simplify an expression
To simplify an expression, do all operations in the expression.
square and square root
If $n2=mn2=m$, then $mm$ is the square of $nn$ and $nn$ is a square root of $mm$.
term
A term is a constant or the product of a constant and one or more variables.
variable
A variable is a letter that represents a number whose value may change.
whole numbers
The whole numbers are the numbers 0, 1, 2, 3, ....
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