D
Data	Collection of information.
Deca/Deka	Prefix meaning 10.
Decagon	Polygon with 10 sides.
Decrease	Get smaller in size or number.
Deduct	To Subtract.
Degree	unit of measuring angles.
Denominator	Bottom number in a fraction.
Descending Order	Arranged from larges to smallest.
Diameter	A line passing all the way across a circle through the center.
Difference	Difference between two numbers(subraction).
Dimension	Refers to height, length, or width.
Distance	Length between two points.
Dozen	A group or set of 12.