D

data

A collection of facts or information. (See also data table.)

data table

A tool for recording and organizing data. (See also data.)

decreasing

Going down in size or amount. For example, in the pattern 10, 8, 6, 4 the numbers are counting down or decreasing by 2.

diagonal

A straight line that goes from corner to corner (not an edge) inside a shape. Or, a stair steps pattern on a chart.

difference

The answer to a subtraction problem.

digital clock

A clock that shows the time using numbers instead of moving hands.

dime

A coin equal to (or worth) 10 cents (10¢).

divide

To separate into equal parts or groups to make "fair shares." (See also fair share.)

dollar

An amount of money equal to (or worth) 100 cents (100¢). The symbol for the dollar is $ ($1.00).

double

Making something twice as big or adding a number to itself. For example, the double of 12 is 24.

doubles

A doubles fact is a number sentence where two of the same numbers are added. For example, 2 + 2 = 4 and 3 + 3 = 6 are doubles facts.