Kilogram : A kilogram or kg is a unit for weight equal to 1,000 grams.

Length : Length is the attribute of a one-dimensional shape that can be measured with a measuring tape.

Measurement : To measure something or to get a measurement is to quantify a physical attribute given a choice of unit using the appropriate tool for measuring that specific physical attribute (for example a scale for weight or a measuring tape for length).

Pound : A pound or $lb$ is a unit for measuring weight. One pound equals 16 ounces or approximately 454 grams.

Scale : Scale refers to the size of a shape. A scale drawing changes a shape to a similar shape of a different size.

Unit : When measuring an attribute a particular unit specifies which size of the specific attribute is represented by the number 1. For example 1 $cm$ equals 10 $mm$, so when changing the unit we will also have to change the quantity to still represent the same measurement.

Weight : Weight refers to the property of objects that can be measured with a scale.

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

Division : Division is the mathematical operation that divides objects equally into groups. More generally $x\div y$ is defined as the number that if multiplied by $y$ equals $x.$

Fraction : A fraction is a number that can be written as $\frac{a}{b}$ with an integer $a$ and a natural numbers $b.$ A fraction $\frac{a}{b}$ is the result of the division $a\div b.$ Examples of fractions are $\frac{1}{2}, -\frac{2}{3}$ and $\frac{3}{2}.$

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

Numerator : The numerator of a fraction $\frac{a}{b}$ is the number $a$ above the fraction bar.

Quarter : One quarter is the number $\frac{1}{4}=0.25.$

Reduced fraction : A reduced fraction (or simplified fraction or fraction in simplified form or fraction in simplest form) is a fraction $\frac{a}{b}$ such that $a$ and $b$ do not have any common factors bigger than 1. For example the reduced fraction of the fraction $\frac{4}{6}$ is $\frac{2}{3}.$

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

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