# Kids Math

## Glossary and Terms: Types of Numbers

**Arithmetic Progression**- A sequence of numbers where the difference between each number is the same.

Example: 3, 6, 9, 12, 15, 18, 21……is an arithmetic progression where the difference is 3.

**Ascending Order**- A list of numbers or values from least to greatest, but doesn't have to have a fixed pattern.

Example: 4, 5, 7, 12, 19, 44, 60

**Binary**- The binary number system is a "base-2" number system. This means there are only two numerals 0 and 1.

Example: 11 binary is the same as 3 decimal, 110 binary is the same as 6 decimal.

**Cardinal Numbers**- A cardinal number answers the question "how many?"

Example: 12 footballs…..12 is a cardinal number

**Composite**- A composite number is a positive integer that has a divisor other than itself and one. A composite number cannot be a prime number.

Example: 20, 12, 55 are all composite numbers. 19 and 31 are NOT composite numbers.

**Decimals**- A decimal is a base-10 number. These are the numbers we use every day.

Example: There are 10 numerals in the decimal numbering system 0,1,2,3,4,5,6,7,8,9

**Decomposing**- When you decompose a number, you break it into its component parts.

Example: 5,124 becomes 5,000 + 100 + 20 + 4

**Descending Order**- A list of numbers or values from greatest to least, but doesn't have to have a fixed pattern.

Example: 88, 45, 44, 31, 12, 7, 2

**Even**- Even numbers can be divided by 2. Zero is also considered an even number. Even numbers end with a 2,4,6,8, or 0.

Example: 2, 4, 26, 38, 90 are all even numbers.

**Fraction**- A number the represents part of a whole.

Example: ¼ + ¾ = 1

**Hexadecimal**- Hexadecimal is a base-16 number system. It has 16 numbers including 0-9 and A, B, C, D, E, F. It is used a lot in computer programming.

Example: FF is the hexadecimal number for 255.

**Infinite**- An infinite number is so large it cannot be counted. An infinite sequence goes on forever. It can be represented by writing three periods …

Example: 1,3,5,7,9, … is an infinite sequence of odd numbers

**Integer**- An integer is a whole number including zero, positive, and negative numbers. Fractions and decimals are not integers.

Example: -5, -1, 0, 12, 472 are all integers

**Irrational Numbers**- An irrational number is a number that can be written as a decimal, but cannot be written as a simple fraction.

Example: The number pi cannot be written as a fraction but is written as a decimal 3.14159…

**Natural or Counting Numbers**- These are the numbers we use all the time for counting. They also could be called positive integers. Sometimes zero is included.

Example: 1,2,3,4,5,6,…

**Numeral**- A numeral is a word or a symbol that represents a number.

Example: The word "eight" and the symbol "8" both are numerals that represent the number 8.

**Octal**- A base-8 number system. This means there are only 8 numbers 0-7. The octal number system is used a lot with computers.

Example: 10 octal is the same as 8 decimal. 20 octal is the same as 16 decimal

**Odd**- Numbers that do not divide evenly by 2. They will have a remainder.

Example: 1,3,5,7,9,11,13,…

**Ordinal**- Ordinal numbers represent the order of items in a set. Rather than represent quantity, they represent the rank or position of something.

Example: Sally was 5th in line or Jim finished 2nd in the race.

**Pi**- Pi is a special number. It is often represented by the symbol Π. It is an irrational number that never ends. It starts out 3.14159, but continues on forever. Pi is useful in solving geometry problems with circles and spheres.

Example: Π = 3.14159…

**Prime**- A prime number is any whole number greater than 1 that only has the number 1 and itself as factors.

Example: The first 8 prime numbers are 2,3,5,7,11,13,17, and 19.

**Rational Number**- A rational number is any number that can be written as a fraction using two integers. Every integer is a rational number.

Example: ¾ or 0.75 is a rational number

**Roman Numerals**- Roman Numerals use letters to represent numbers. Click on Roman Numbers for Kids to learn more.

Example: V = 5, XX = 20

**Standard Form**- Standard form is an agreed upon way to write things. With numbers, this is often written with a comma every three places.

Example: 3,000,000 is standard form for writing three million

**Whole Number**- Any number that does not have a decimal or fraction portion.

**More Math Glossaries and Terms**

Algebra glossary

Angles glossary

Figures and Shapes glossary

Fractions glossary

Graphs and lines glossary

Measurements glossary

Mathematical operations glossary

Probability and statistics glossary

Types of numbers glossary

Units of measurements glossary

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