Fractions – Multiplying – Complete Lesson Preview the presentation to check ability-level, AFL questions, and the animations during demonstrations. It is recommended to delete slides/sections not needed for your class.

Starter A task at the beginning of the lesson that reviews a skill required for the learning. Knowledge Check Questions to assess students’ current understanding and to consequently show progress. Real-Life Example A ‘hook’ to raise interest and provide a concrete example. Demonstration Slides for a teacher to lead students – didactically or via questioning – through a mathematical method. AFL Questions Assessment For Learning Questions, used to assess students’ competency for independent tasks/activities. Plenary An opportunity for students to prove/evaluate their learning.

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10 x3 ÷2 -5 x2 x5 +5 ÷5 16 ?? ÷10 -5 x8

Multiplying Fractions 30 July 2019 Multiplying Fractions

KNOWLEDGE CHECK 1 3 × 2 5 = 3 4 × 4 5 = 2 5 ÷ 1 6 =

KNOWLEDGE CHECK 1 3 × 2 5 = 2 15 3 4 × 4 5 = 12 20 = 6 10 = 3 5 2 5 ÷ 1 6 = 12 5 =2 2 5

1 3 of 1 4 means 1 3 × 1 4 = 1 12 Georgie took a 1 4 of the cake! She split the piece into 3 and gave one piece each to Tom and Rob. How big was the piece Tom ate? 1 3 of 1 4 means 1 3 × 1 4 = 1 12

Area = 8 × 6 = 48 metres2 How do we find the area of a field? 8 metres

We can see it is a quarter of the whole field. What if we want to find the area of half the length, and half the width? 4 metres 3 metres We can see it is a quarter of the whole field.

? 1 4 1 5 1 6 What if we want to find the area of half the length, and a third of the width? What fraction of the field is the area? 1 4 1 5 1 6 ? or or

This is an easy way to multiply fractions. 1 2 1 3 1 2 × 1 3 = 1 6

What is the fraction for… 1 2 × 1 4 = 1 8 1 2 × 1 5 = 1 10 1 2 1 2 1 4 1 5

What is the fraction for… 1 3 × 1 4 = 1 12 2 3 × 1 4 = 2 12 1 3 2 3 1 4 1 4

Draw diagrams in your books to help calculate the answers. 1) 2) 1 4 1 3 × 1 3 = 1 4 × 1 5 = 1 5 3) 3) 1 3 × 2 3 = 3 4 × 2 3 =

Answers Draw diagrams in your books to help calculate the answers. 1) 2) 1 3 1 4 1 3 × 1 3 = 1 9 1 4 × 1 5 = 1 20 1 3 1 5 3) 3) 1 3 3 4 1 3 × 2 3 = 2 9 3 4 × 2 3 = 6 12 2 3 2 3 Can we make this fraction simpler? Answers

Can we write a rule for multiplying fractions, Draw diagrams in your books to help calculate the answers. 1) 2) 1 3 1 4 1 3 × 1 3 = 1 9 1 4 × 1 5 = 1 20 1 3 1 5 Can we write a rule for multiplying fractions, just using numbers? 3) 3) 1 3 3 4 1 3 × 2 3 = 2 9 3 4 × 2 3 = 6 12 2 3 2 3 Can we make this fraction simpler? Answers

Is Anna right? 1 3 × 2 3 = 2 9 To multiply fractions, 1 3 × 2 3 = 2 9 2 3 To multiply fractions, multiply the numerator, then multiply the denominator. ANNA says…. Is Anna right?

To quickly multiply fractions we multiply the numerators and multiply the denominators (1 x 1) (1) 1 2 × 1 3 = 1 6 (6) (2 x 3)

To quickly multiply fractions we multiply the numerators and multiply the denominators (1 x 2) (2) 1 3 × 2 3 = 2 9 (9) (3 x 3)

To quickly multiply fractions we multiply the numerators and multiply the denominators (1 x 2) Can we simplify this fraction? (2) 1 4 × 2 3 = 2 12 = 1 6 (12) (4 x 3)

To quickly multiply fractions we multiply the numerators and multiply the denominators (2 x 1) Can we simplify this fraction? (2) 2 3 × 1 5 = 2 15 (15) (3 x 5)

To quickly multiply fractions we multiply the numerators and multiply the denominators (3 x 2) Can we simplify this fraction? (6) 3 4 × 2 5 = 6 20 = 3 10 (20) (4 x 5)

To quickly multiply fractions we multiply the numerators and multiply the denominators (5 x 3) Can we simplify this fraction? (15) 5 6 × 3 5 = 15 30 = 1 2 (30) (6 x 5)

What’s wrong? What’s the answer? 2 3 × 4 5 = 6 15 8 15 Sarah 2 3 × 3 5 = 6 15 Julie 2 5

3 4 × 1 6 = 4 5 × 1 6 = 5 6 × 2 7 = 1 3 × 1 5 = 5 7 × 5 6 = 2 3 × 1 4 = 1 1 2 × 3 4 = 3 4 × 2 5 = 2 3 4 ×1 1 2 =

3 4 × 1 6 = 3 24 = 1 8 4 5 × 1 6 = 4 30 = 2 15 5 6 × 2 7 = 10 42 = 5 21 Answers 1 3 × 1 5 = 1 15 5 7 × 5 6 = 25 42 2 3 × 1 4 = 2 12 = 1 6 1 1 2 × 3 4 = 9 8 =1 1 8 3 4 × 2 5 = 6 20 = 3 10 2 3 4 ×1 1 2 = 33 8 =4 1 8

1 2 𝑜𝑓 1 3 1 2 × 1 3 = 1 6 Ben, Bob and Bill split a pizza equally. Ben gave half his pizza to his sister, Anna. What fraction of the whole Pizza did Anna get? Ben Bob Bill Anna 1 2 𝑜𝑓 1 3 1 2 × 1 3 = 1 6 Anna got 1 6 of the whole pizza.

Jim, Jane, Jack and John split a pizza equally. Jim gave half his pizza to his brother, David. What fraction of the whole Pizza did David get? Jim Jane Jack John David 1 2 𝑜𝑓 1 4 1 2 × 1 4 = 1 8 David got 1 8 of the whole pizza.

Mary split her birthday cake into 8 equal pieces. Sally split one of the pieces into two. What fraction of the whole cake is one of Sally’s pieces? 1 8 1 16 1 2 𝑜𝑓 1 8 1 2 × 1 8 = 1 16

Mary split her birthday cake into 7 equal pieces. Sally split one of the pieces into 3. What fraction of the whole cake is one of Sally’s pieces? 1 7 1 21 1 3 𝑜𝑓 1 7 1 3 × 1 7 = 1 21

Calculate 1 3 of 1 2 1 3 1 6 1 3 𝑜𝑓 1 2 1 3 × 1 2 = 1 6

Calculate 1 4 of 1 3 1 3 1 12 1 4 𝑜𝑓 1 3 1 4 × 1 3 = 1 12

Calculate 1 4 of 2 3 2 3 1 12 1 12 1 4 𝑜𝑓 2 3 1 4 × 2 3 = 2 12 = 1 6

Calculate 3 4 of 2 3 2 3 1 12 1 12 1 12 1 12 1 12 1 12 3 4 𝑜𝑓 2 3 3 4 × 2 3 = 6 12 = 1 2

Draw diagrams in your books to help calculate the answers. 1 2 of 1 3 = 2 5 of 1 4 = 2 3 of 3 4 = 1 5 of 1 2 = 1 3 of 2 3 = 4 5 of 3 4 =

Draw diagrams in your books to help calculate the answers. 1 2 of 1 3 = 1 6 2 5 of 1 4 = 2 20 = 2 20 2 3 of 3 4 = 6 12 = 1 2 1 5 of 1 2 = 1 10 1 3 of 2 3 = 2 9 4 5 of 3 4 = 12 20 = 3 5

× = × = × = × = × = = × = × = = × = Multiplying Fractions : Amber 1. a) 4 2 b) 1 5 1. a) 4 2 b) 1 5 × = × = × = × = 5 15 7 14 5 15 7 14 Simplify! Simplify! c) 2 5 2 8 × = = d) × = c) 2 5 × = = d) 2 8 × = 5 6 3 27 5 6 3 27 3. Calculate the area of this rectangle. 3. Calculate the area of this rectangle. 5 7 × 3 4 = 5 7 × 3 4 = 2. a) 2. a) 5 6 m 5 6 m 6 7 × 4 9 = 3 4 m 6 7 × 4 9 = b) b) 3 4 m Multiplying Fractions : Green Multiplying Fractions : Green 5 7 × 3 4 = 6 7 × 2 3 = 5 7 × 3 4 = 6 7 × 2 3 = 1. a) b) 1. a) b) 4 9 × 3 8 = 7 10 × 5 7 = 4 9 × 3 8 = 7 10 × 5 7 = c) d) c) d) 1 2 3 × 3 4 = 1 2 3 × 3 4 = 2. a) How can we calculate this? 2. a) How can we calculate this? 1 3 4 × 3 5 = 1 4 5 ×1 2 7 = 1 3 4 × 3 5 = 1 4 5 ×1 2 7 = b) c) b) c) 3. a) Can we make this calculation easier before multiplying? (Look again at Question 1 part d) 3. a) Can we make this calculation easier before multiplying? (Look again at Question 1 part d) 4 5 × 3 4 = 4 5 × 3 4 =

× = × = × = = × = Multiplying Fractions : Amber 1. a) 4 2 1 5 b) 5 15 7 14 Simplify! c) 2 5 2 8 × = = d) × = 5 6 3 27 3. Calculate the area of this rectangle. 5 7 × 3 4 = 2. a) 5 6 m 6 7 × 4 9 = b) 3 4 m Multiplying Fractions : Green 5 7 × 3 4 = 6 7 × 2 3 = 1. a) b) 4 9 × 3 8 = 7 10 × 5 7 = c) d) 1 2 3 × 3 4 = 2. a) How can we calculate this? 1 3 4 × 3 5 = 1 4 5 ×1 2 7 = b) c) 3. a) Can we make this calculation easier before multiplying? (Look again at Question 1 part d) 4 5 × 3 4 =

Answers × = × = × = = × = Multiplying Fractions : Amber 1. a) 4 2 8 5 3 15 7 2 14 Simplify! c) 2 5 10 1 d) 4 2 8 × = = × = 5 6 30 3 9 3 27 3. Calculate the area of this rectangle. 5 7 × 3 4 = 15 28 2. a) 15 24 = 5 8 m2 5 6 m 6 7 × 4 9 = 24 63 = 8 21 b) 3 4 m Multiplying Fractions : Green 5 7 × 3 4 = 15 28 6 7 × 2 3 = 12 21 = 4 7 1. a) b) 4 9 × 3 8 = 12 72 = 1 6 7 10 × 5 7 = 35 70 = 1 2 c) d) 1 2 3 × 3 4 = 5 3 × 3 4 = 15 12 = 5 4 =1 1 4 2. a) How can we calculate this? 1 3 4 × 3 5 = 21 20 =1 1 20 1 4 5 ×1 2 7 = 81 35 =2 11 35 b) c) 3. a) Can we make this calculation easier before multiplying? (Look again at Question 1 part d) 4 5 × 3 4 = 3 5

Answers

Answers

1 4 of 1 5 means 1 4 × 1 5 = 1 20 Georgie took a 1 5 of the cake! She split the piece into 4 and gave one piece to Tom, Ann and Rob. How big was the piece Ann got? 1 4 of 1 5 means 1 4 × 1 5 = 1 20

Check your success! I can multiply fractions with 1 as the numerator. I can multiply fractions with any numerator. I can multiply mixed numbers.

Check your success! I can multiply fractions with 1 as the numerator. I can multiply fractions with any numerator. I can multiply mixed numbers.

How to multiply fractions. Write a text message to a friend describing… How to multiply fractions.

tom@goteachmaths.co.uk Questions? Comments? Suggestions? …or have you found a mistake!? Any feedback would be appreciated . Please feel free to email: tom@goteachmaths.co.uk