# Pre-Kindergarten - Grade 2 Math

## Glossary of Terms

**Area** – the amount of space inside a flat figure like a square or triangle, measured in square inches, etc.

**Base ten blocks** – a set of classroom hands-on materials that represent ones, tens and hundreds as small cubes (ones), rods of 10 small cubes combined (tens), and squares of ten rods combined (hundreds).

**Circumference** – the distance around the outside of a circle.

**Common Core State Standards** – provide a set of clear and consistent expectations that outline the knowledge and skills students need in the 21st century to be career and college ready.

**Decimal numbers **– Numbers that use a decimal point, such as 3.45 for 3 and 45 hundredths.

**Denominator** – the bottom number of a fraction.

**Fluency** – knowing addition and multiplication facts quickly and accurately, usually from memory. (also: fluently)

**Function** – a mathematical expression that relates two quantities, such as the distance and time that a car travels.

**Graduated series** – sorting numbers or objects into increasing or decreasing order

**Mean**– the average of a set of data

**Median** – the middle number of a set of data when arranged in numerical order

**Negative numbers** – numbers that are smaller than zero, such as negative temperatures (e.g. -10 degrees)

**Number line** – a straight line marked in equal intervals and labeled with consecutive numbers.

**Numerator** – the top number of a fraction

**Parallel lines** – lines that never cross

**Perimeter**– the distance around the outside of a figure. For example, a square where each side is 10 inches has a perimeter of 40 inches.

**Perpendicular lines** – lines that cross at right angles.

**Proof **(in geometry) – a formal method of reasoning to support a claim

**Proportion or proportional relationship** – two quantities that increase or decrease at the same rate.

**Pythagorean Theorem **– The relationship between the length of the sides of any right triangle. If the sides are labeled a, b and c, where c is the longest side, then the relationship is a2 + b2 = c2.

**Quadrilateral **– any four-sided figure like a square, rectangle, parallelogram, etc.

**Rhombus** – a four-sided figure where all sides are the same length (like a square) but the angles are not necessarily right angles.

**Rotations, reflections, translations and dilations** – ways of moving geometric figures to produce similar figures in different places, orientations or sizes. (also: transformations)

**Scatter plot** – a way of representing a set of data that has two components, such as the size and cost of cars.

**Scientific notation** – a method for writing large numbers that uses a power of ten to show how many zeros or places are in the number. For example, 3,000,000 can be written as 3 x 106.

**Strategies** – Using counting or known math facts to figure out math problems. (also: mental math strategies)

**Surface area** – the total area of the outside of a three-dimensional object like a box or bottle.

**Volume** – the amount of space inside a three-dimensional object like a box or bottle.