Adding and Subtracting Fractions

Adding and Subtracting Fractions

• 1.
  Adding and subtractingsimple fractions In today's lesson we covered the addition and subtraction of simple fractions (fractions where the denominator are the same). Keywords (learn these!): Denominator – The bottom number of a fraction. Numerator – The top number of a fraction.
• 2.
  When fractions havethe same denominator it is quite easy to add them together and to subtract them. For example, + = = We can show this calculation in a diagram: + = Adding and subtracting simple fractions Denominator – The bottom number of a fraction. Numerator – The top number of a fraction. 3 5 1 5 3 + 1 5 4 5
• 3.
  Adding and subtractingsimple fractions = = Fractions should always be cancelled down to their lowest terms. 1 2 = We can show this calculation in a diagram: – = Denominator – The bottom number of a fraction. Numerator – The top number of a fraction. 7 8 – 3 8 7 – 3 8 4 8 1 2
• 4.
  Adding and subtractingharder fractions In today's lesson we also covered the addition and subtraction of harder fractions (fractions where the denominator are not the same). Keywords (learn these!): Denominator – The bottom number of a fraction. Numerator – The top number of a fraction. Equivalent – The same as
• 5.
  We can changea fraction into another fraction which is an equivalent fraction (the same fraction) by multiplying or dividing the numerator and denominator by the same number. Adding and subtracting simple fractions Denominator – The bottom number of a fraction. Numerator – The top number of a fraction. Equivalent – The same as. 3 4 = 6 8 = 18 24 For example: To find an equivalent fraction we must multiply or divide the denominator and numerator by the same number. × 2 × 2 × 3 × 3
• 6.
  We can use equivalent fractions to add fractions that do not have the same denominator . Adding and subtracting simple fractions 3 4 + 1 8 For example: Denominator – The bottom number of a fraction. Numerator – The top number of a fraction. Equivalent – The same as. 3 4 = 6 8 Now we have: + + 1 8 6 8 = 7 8 We need to change into an equivalent fraction with a denominator of 8. 3 4 × 2 × 2