Consecutive numbers : Two integers are consecutive if you get the second integer by adding 1 to the first integer.

Number : A number $x$ is a mathematical symbol representing a quantity.

Decimal : A decimal is a number represented by digits in front and after a decimal point. In front of the decimal point the digits are the ones digit, tens digit, hundreds digit and so on. After the decimal point there are the tenths digit, hundredths digit, thousandths digit and so on. For example the decimal 1.3 can be written as $1\frac{3}{10}.$

Denominator : The denominator of a fraction $\frac{a}{b}$ is the number $b$ below the fraction bar.

Equivalent fraction : Equivalent fractions are fractions that represent the same number. For example the fractions $\frac{1}{2}$ and $\frac{2}{4}$ are equivalent. One can create equivalent fractions of a fraction by multiplying or dividing both the numerator and the denominator of the fraction by the same non-zero number.

Expression : An expression is a succession of constants, variables and mathematical operations that if evaluated for specific values of the variables represents a number.

Squared : $x$ squared refers to the number $x^2=x\cdot x.$ For example 3 squared equals 9.

Variable : A letter in an expression or function that represents an arbitrary number.