Fractions

• Mathematics
• Primary Education

Fractions

Fraction

• Do you know any words in English that start with fract-?
• Fracture
• What is a fracture?

A fraction is...

• A whole divided into equal parts
• The parts must be equal
• English words for fractions are usually the number + -th
• For example sixth, tenth, hundredth, thousandth
• Irregular words are half, third, quarter. 

Names of fractions

Let's practice naming fractions. 

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Unit fractions

Unit fractions include

• The top number (1) is called the numerator.
• This tells us how many parts there are.
• The bottom number is the denominator.
• This is the total number of equal parts.  
• What word can you see in denominator?
• Nominate - what does this word mean?
• The line between the numerator and denominator means divide. 

​2​​1​​

​3​​1​​

​4​​1​​

Half

This means 1 divided by 2.

​2​​1​​

Fractions

• This KitKat has been divided into 4 equal parts.
• Each part is therefore 1/4. 
• Or a quarter. 
• How could you divide the KitKat into 8 equal parts?
• Which is bigger: 1/4 or an 1/8?

Key fact

• The bigger the denominator the smaller the fraction.
• 1/3 is smaller that 1/2
• 1/3 is bigger than 1/4
• 1/5 is bigger than 1/10

Which is bigger?

1. 1/2
2. 1/8

Which is bigger?

1. 1/2
2. 1/4

Which is bigger?

1. 1/16
2. 1/4

Which is bigger?

1. 1/64
2. 1/4

Which is bigger?

1. 1/8
2. 1/4

Which is bigger?

1. 1/8
2. 1/16

Equivalent fractions and simplifying fractions

• Simplifying fractions is reducing fractions to their simplest form.
  
• To do this we look at the numerator (the top number) and the denominator (the bottom number) and find a common factor that we can use to cancel the fraction down to its lowest terms. The numerator and denominator are always whole numbers
• For example, the fraction 5/10  can be simplified to 1/2  as both the numerator and denominator have 5 as a factor.

Divisibility facts

• These facts can help to identify common factors. 
• We must divide the numerator and denominator by the same number

Even numbers can be divided by 2. They end in 2, 4, 6, 8 and 0. Write some even numbers below.

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Numbers that end in 5 or 0 can be divided by 5. List some of these below.

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Numbers can be divided by 3 if...

• The sum of their digits adds up to 3, 6 or 9
• For example, 21 can be divided by 3 because 2 +1= 3
• 402 can be divided by 3 because 4+0+2= 6
• 432 can be divided by 3 because 4+3+2= 9

List some numbers that can be divided by 3 below.

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Numbers can be divided by 6 if...

• The sum of their digits adds up to 3, 6 or 9 
• AND
• If they are even
• So 432 can be divided by 6
• 504 can be divided by 6

Think of a number that can be divided by 6.

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Numbers can divide by 9 if...