Centimeter : A centimeter ($cm$) is $\frac{1}{100}$ of a meter.

Cubic centimeter : A cubic centimeter or $cm^3$ is a unit to measure volume. A cubic centimeter is the volume of a cube with edge length 1 centimeter and we have $1,000,000 cm^3=1 m^3.$

Height : In a triangle a height (or altitude) is the shortest line segment that connects a side to its opposing corner. A height of a triangle is perpendicular to the side is started at. The three heights of a triangle intersect in a point, the so called orthocenter of the triangle. In a parallelogram the height is the shortest distance between two opposing sides. In a pyramid the height is the shortest distance between the base area and the corner of the pyramid that is not part of the base area. In a prism the height is the shortest distance between the two base faces.

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

Product : A product is the result of a multiplication.

Rectangular prism : A rectangular prism is a prism that has rectangular bases.

Volume : Volume refers to the size of a three-dimensional objects measured by how many unit cubes it would take to fill the shape.

Common denominator : The common denominator of two or more fractions is a number that is a multiple of all the denominators of the fractions. For example 12 and 24 are both common denominators of $\frac{3}{4}$ and $\frac{1}{6}.$

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.

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 $\frac{2}{3}.$

Estimation : Estimation is another word for finding a close but not necessarily exact solution to an arithmetic problem.

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

Ones digit : The first digit left of the decimal point (or the digit furthest to the right if there is no decimal point). It counts multiples of 1.

Rounding : Rounding is the operation of changing a number to a number that is close to the original number. Rounded numbers are often used to do quick rough calculations for estimation purposes. For example rounding $4549$ to the nearest thousand results in 5000, rounding the same number to the nearest hundred results in 4500. In general one rounds up if the digit after the digit we try to round to is 5 or more, otherwise one rounds down.

Significant figure : Rounding a number to k significant figures means that one leaves the first $k-1$ digits unchanged and rounds the k-th digit up if the (k+1)-th digit is at least 5 and rounds it down otherwise. For example rounding the number 1234 to 2 significant digits results in 1200.

Thousandths digit : The thousandths digit is the third digit after the decimal point. It counts multiples of $\frac{1}{1,000}.$