1.2 Natural Numbers

Prime Number

Anumber which can be divided evenly only by 1, or itself. It must be a whole number greater than 1.

Even Number

Any integer (not a fraction) that can be divided exactly by 2. The last digit is 0, 2, 4, 6 or 8

Odd Number

Any integer (not a fraction) that cannot be divided exactly by 2. The last digit is 1, 3, 5, 7 or 9

Ascending

Becoming bigger

Descending

Becoming smaller

Estimating

Finding a value that is close enough to the right answer, usually with some thought or calculation involved.

Place Value

In the number 555, each 5 in a different place has a different value.

Rounding

Making a number simpler but keeping its value close to what it was. It is the best known estimation method.

Consecutive Numbers

Numbers which differ by one e.g., 5, 6, and 7

Factor

Numbers you can multiply together to get another number

Lowest Common Multiple (LCM)

The LCM of two or more numbers is the smallest number that these numbers will divide into exactly. Example: the LCM of 3 and 5 is 15, because 15 is a multiple of 3 and also a multiple of 5.

Square Root

The _________________ of a number is a value that, when multiplied by itself, gives the number. Example: 4 × 4 = 16, so √16 is 4. The symbol is √

Quotient

The answer after you divide one number by another

Product

The answer when two or more numbers are multiplied together.

Highest Common Factor (HCF)

The highest number that divides exactly into two or more numbers. Abbreviated "HCF". Example: the HCF of 12 and 16 is 4, because 1, 2 and 4 are common factors of both 12 and 16, and 4 is the greatest.

Square Number

The number we get after multiplying an integer (not a fraction) by itself.

Divisor

The number you divide by dividend ÷ divisor = quotient Example: in 12 ÷ 3 = 4, 3 is the ______________

Subtraction

The operation or process of finding the difference between two numbers or quantities, represented by a minus sign (−). Taking one number away from another. It is the opposite or inverse of addition.

Inverse Operation

The operation that reverses the effect of another operation. Addition and subtraction are examples of this. Multiplication and division are also examples of this.

Indices

The plural of index

Sum

The result of adding two or more numbers.

Multiple

The result of multiplying a number by an integer (not by a fraction). Examples: • 12 is a ______________ of 3, as 3 × 4 = 12

Difference

The result of subtracting one number from another. How much one number differs from another.

Order of Operations (BIMDAS)

The rules that say which calculation or operation comes first in an expression: - Brackets - Indices - Multiplication - Division - Addition - Subtraction

Numeral

The symbols we use to denote numbers.

Natural Numbers

They are represented by the set N={1, 2, 3, 4, 5, 6, 7,...} This is an infinite set.

Multiplication

This is repeated addition of numbers or getting the product of those numbers. It is the opposite or inverse of division.

Division

This is splitting into equal parts or groups. It is the result of "fair sharing". It is the opposite or inverse of multiplication We use the ÷ symbol, or sometimes the / symbol. 12 / 3 = 4 12 ÷ 3 = 4

Index

This says how many times to multiply the number by itself. It is written as a small number to the right and above the base number. It is also known as a power or exponent.

Array Method

Using rows and columns to help with multiplication.

Base Ten

We count in tens, probably because most people have ten 'digits' on their hands.

Prime Factor

A factor that is a prime number: one of the prime numbers that, when multiplied, give the original number.

Twin Primes

A pair of primes that differ by 2. For example, 3 and 5 or 17 and 19.

Number Line

A way of helping us to put numbers in order. Numbers get bigger from left to right. Numbers get smaller from right to left.

Composite Number

A whole number that can be divided evenly by numbers other than 1 or itself.

Operation

An action or procedure which produces a new value from input values.

Addition

An example of an operation. It is often represented by + symbol. It is finding the total, or sum, by combining two or more numbers. It is the opposite or inverse of subtraction.