# Fractions, Decimals & Percentages 1 Mr. Roche: 1st Year maths.

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Fractions, Decimals & Percentages 1 Mr. Roche: 1st Year maths

2 Fractions Must be able to: 1.Change Mixed Numbers into Improper Fractions 2.Change Improper Fractions into Mixed Numbers 3.Multiply Fractions 4.Divide Fractions 5.Add/Subtract Fractions

3 Mr. Roche: 1st Year maths 1.Change Mixed Numbers to Improper Fractions E.g. Change into an improper fraction. + x = 5 3(5) = 15 15 + 2 = 17 17 The Denominator doesn’t change

4 Mr. Roche: 1st Year maths 2.Change Improper Fractions to Mixed Numbers E.g. Change into a mixed number. = 4 Denominator ? Denominator ? What is the shape of the answer? The Denominator doesn’t change Now Divide: 13 ÷ 4 Now Divide: 13 ÷ 4 13 ÷ 4 = 3 Times Remainder 1 13 ÷ 4 = 3 Times Remainder 1 3 Whole Number ? Whole Number ? 1 Numerator ? Numerator ?

5 Mr. Roche: 1st Year maths 3.Multiply Fractions E.g. Multiply Step 1 Look for cancellations Step 1 Look for cancellations 1 2 Step 1 3 ÷ 3 = 1 6 ÷ 3 = 2 Step 1 3 ÷ 3 = 1 6 ÷ 3 = 2 Step 2 Multiply Top x Top Bottom x Bottom Step 2 Multiply Top x Top Bottom x Bottom = 5 Step 2 Multiply 1 x 5 = 5 4 x 2 = 8 Step 2 Multiply 1 x 5 = 5 4 x 2 = 8 8

Step 2 Look for cancellations Step 2 Look for cancellations 6 Mr. Roche: 1st Year maths 3.Divide Fractions E.g. Divide 1 2 = 8 Step 1 Rewrite: “Invert and Multiply” Step 1 Rewrite: “Invert and Multiply” = Step 2 10 ÷ 5 = 2 5 ÷ 5 = 1 Step 2 10 ÷ 5 = 2 5 ÷ 5 = 1 Step 3 Multiply Top x Top Bottom x Bottom Step 3 Multiply Top x Top Bottom x Bottom Step 3 Multiply 3 x 1 = 3 2 x 7 = 14 Step 3 Multiply 3 x 1 = 3 2 x 7 = 14 3 14

7 Mr. Roche: 1st Year maths 5. Add/Subtract Fractions E.g. Add Step 1 Find the L.C.D. Step 1 Find the L.C.D. Consider the multiples of the bigger denominator 6 12 18 24 Consider the multiples of the bigger denominator 6 12 18 24 12  LCD? Step 2 Divide & Multiply Step 2 Divide & Multiply 12 ÷ 4 = 3 1 x 3 = 3 3 + 12 ÷ 6 = 2 2 x 5 = 10 10 Step 3 Add or Subtract Step 3 Add or Subtract

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