📖Definition
There are various types of number eg. even, negative, prime and they each have different properties.
Knowing these properties can save you time.
Odd and Even Numbers
An Even number can be divided by 2 with no remainder.
The Even Numbers start 2, 4, 6, 8, 10, 12, 14, ...
Even numbers end in a 2, 4, 6, 8 or 0
An Odd number leaves a remainder of 1 when divided by 2.
The Odd Numbers start 1, 3, 5, 7, 9, 11, 13, ...
Odd numbers end in a 1, 3, 5, 7 or 9
All whole numbers are either Even or Odd.
Addition Properties
When you add whole numbers together, you can tell whether the result will be even or odd just by knowing if the numbers you're adding are even or odd.
Odd + Even = Odd
Even + Even = Even
Odd + Odd = Even
💡Multiplication Properties
The same goes for multiplying.
Any x Even = Even
Odd x Odd = Odd
If the product of a set of numbers is Even then at least one of those numbers is Even
If the product of a set of numbers is Odd then ALL the numbers must be Odd.
Negative Numbers
Negative numbers are those which are less than 0. We use them in everyday life for example to tell the temperature on a very cold day.
When adding or subtracting negative numbers, it can be helpful to use a number line.
And don't forget, the larger the number part of a negative number is, the smaller the actual number.
Prime Numbers
A prime number is a number that has exactly two factors. It only divides by 1 and itself.
The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29...
Note that 1 is NOT a prime number (it only has one factor).
Square Numbers
A whole number times itself produces a Square Number
1 x 1 = 1
2 x 2 = 4
3 x 3 = 9 etc.
So, 1, 4 and 9 are Square Numbers,
The first ten Square Numbers are:
1, 4, 9, 16, 25, 36, 49, 64, 100
The number we multiply by itself to get the square is called the Square Root so, 2 is the Square Root of 4, 5 is the Square Root of 25.
✏️Example
Yesterday it was -2°C and today it is 3° lower. What is today's temperature?
✅Solution
Using a number line, the numbers get smaller as we move from right to left so to find 3 less than -2, start at -2 and move 3 steps to the left, ie to -5.
Diagram
So, today's temperature is -5°C
✏️Example
81, 64, 49, 36, 16
Which of these numbers is the Square of a Prime?
✅Solution
Let's find out what each number is the Square of.
81 = 9 x 9
64 = 8 x 8
49 = 7 x 7
36 = 6 x 6
16 = 4 x 4
The only one of those that appears in the list of Prime Numbers is 7 so 49 is our answer.