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A Glossary of Mathematical Terms - D

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Decagon

A ten-sided polygon.

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Decimal

Decimals are numbers with decimal points.

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Decimal fraction

A fraction whose denominator is a power of 10.

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Denominator

See Fraction

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Diagonal

In polygons: a segment connecting two non consecutive vertices.

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Difference

See Subtraction.

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Digit

Digits are the symbols used to write numerals in a number
system: in the usual (base10) system they are 0, 1, 2, 3, 4, 5,
6, 7, 8, 9.

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Dilation (Dilatation)

A geometric transformation where figures are enlarged or
reduced.

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Discount

A percentage subtracted from a number.

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Disjoint sets

Sets that have non common elements.

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Distributive property

A property that links two operations (e.g. addition and
multiplication betwen numbers: a(b+c)=ab+ac).

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Dividend

See Division

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Divisibility rules

Patterns that allow us to determine wheter or not a number
divides evenly into another number, without actually doing the
division.

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Division

6 divided by 2: 6/2;

the quotient of 6 and 2 is 3: 6/2=3

the ratio of 6 to 2 is 3: 6/2=3;

the outcome of the division is the quotient;

the first term is the dividend;

the second term is the divisor.

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Divisor

See Division and Factor.

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Dodecagon (Duodecagon)

A twelve-sided polygon.

copyright 2000 et seq. maddalena falanga & luciano battaia

first published on september 01 2003 - last updated on september 01
2003