Abacus- An abacus has beads that slide on rods. It can be used to count, add, subtract, multiply and more.

Acceleration- How fast velocity changes.

Acute angle- An angle less than 90° (90° is called a Right Angle).

Add- To bring two or more numbers together.

Addition- Finding the total, by combining two or more numbers.

Adjacent- Lying next to each other.

Algebra- Algebra uses letters or other symbols in place of values, and then plays with them using special rules.

Algorithm- A step-by-step solution.

Balance- When both sides have the same quantity or mass.

Bank- Banks look after peoples money, give loans and have other financial services.

Bar graph- A graph drawn using rectangular bars to show how large each value is.

Base- The surface a solid object stands on, or the bottom line of a shape such as a triangle or rectangle.

Bias- A systematic (built-in) error which makes all values wrong by a certain amount.

Billion- A thousand millions.

Binary- Binary Numbers use only the digits 0 and 1.

Calculate- To work out an answer, usually by adding, multiplying etc.

Calendar- A diagram that shows what day and month it is.

Capacity- The amount that something can hold.

Cardinal Number- Cardinal numbers say how many of something there are, such as one, two, three.

Celsius- Celsius is a temperature scale.

Century- One hundred years.

Closure- Closure is an idea from Sets.

Data- A collection of facts, such as numbers, words, measurements, observations or even just descriptions of things.

Date- The exact day, month and/or year.
Day- The 24 hour period from midnight to the next midnight. Or any 24-hour period.

Decade- A period of 10 years.

Decimal- Based on 10.

Degree- How precise a measurement is, often shown as the number of decimal places or significant digits.

Denominator- The bottom number in a fraction.

Edge- A line segment on the boundary joining one vertex (corner point) to another.

Element- A member of a set.

Equal- Exactly the same amount or value.

Equivalent- Having the same value.

Error- The difference between the actual and measured value.

Estimate- To find a value that is close enough to the right answer, usually with some thought or calculation involved.

Face- Any of the individual flat surfaces of a solid object.

Factor- Numbers we can multiply together to get another number.

Finite- Not infinite. Has an end. Could be measured, or given a value.

First- Before anything else.

Formula- A rule or fact written with mathematical symbols.

Fraction- Parts of a whole.

Gallon- A unit of volume for measuring liquids.

Geometry- The branch of mathematics that deals with points, lines, shapes and space.

Goniometer- An instrument for measuring angles between surfaces.

Gram- A Metric measure of mass (which we feel as weight).

Graph- A diagram of values, usually shown as lines.

Grid- A set of lines used to help us accurately draw graphs etc.

Half- One of two equal parts of a whole.

Handspan- The distance from the tip of the thumb to the tip of the little finger on your outstretched hand.

Hectogon- A 100-sided polygon (a flat shape with straight sides).

Height- The distance from top to bottom.

Hexagon- A 6-sided polygon (a flat shape with straight sides).

Horizontal- Going side-to-side, like the horizon.

Hour- A period of time equal to 1/24 (a twenty-fourth) of a day.

Hundred- Ten times ten

Identity- An equation that is true no matter what values are chosen.

Inch- A measure of length (or distance) in US units.

Income- Money earned from working, investments or doing business.

Increase- Make something bigger (in size or quantity).

Infinite- Without an end. Not finite.

Integer- A number with no fractional part (no decimals).

Intersect- To cross over (have some common point).

Kilogram- A Metric measure of mass (which we feel as weight).

Kiloliter- A Metric measure of volume. Equal to 1,000 liters.

Kilometer- A Metric measure of distance. Equal to 1,000 meters.

Knot- A unit of speed equal to one nautical mile per hour, or 1.151 mph (approximately), or 1.852 km/h (exactly).

Lakh- One hundred thousand.

Least- Smallest.

Length- Distance. How far from end to end. Or from one point to another.

Line-  A long thin mark made by a pen, pencil, etc.

Liter- A Metric unit of volume.

Mass- A measure of how much matter is in an object.

Math- The study of numbers, patterns, space, and change.

Maximum- The largest value.

Measure- To find a number that shows the size or amount of something.

Meter- The basic unit of length in the Metric System.

Millennium- A period of time of a thousand years.

Minute- A unit of time equal to 60 seconds.

Multiplication- Repeated addition.

Number line- A line with numbers placed in their correct position.

Numeral- A symbol or name that stands for a number.

Numerator- The top number in a fraction.