Lesson plan: Chocoholics

Song Bank link

Chocoholics by Maurice Walsh

Subject links

• Maths

Duration

1 hour

Learning Objectives

• Understand that division is the inverse of multiplication and vice versa.

• Solve one-step and two-step number problems, choosing and carrying out appropriate calculations.
  
  

Resources

• Props suitable for demonstrating doubling/halving, eg. cake cut-out, bag of ‘sweets’   

• Chocoholics audio tracks and lyrics

• A3 image of 24-piece chocolate bar (pre-cut) for whole-class demonstration

• A5 image of 24-piece chocolate bar (1 per pair)

• Pupil whiteboards and pens (1 each)

• Pairs of scissors (1 per pair)
  
  

Introduction

• Share the Learning objectives with the children.

• Recap previous work from Year 2, that halving is the inverse of doubling. Use shapes (eg. a cake, a pizza) and then numbers (eg. a bag of sweets). Begin using visual props, then encourage children to work out doubles and halves mentally.  Use the terms ‘sharing’ and ‘dividing’ – how many have we been sharing between, or dividing by? (Two.)
  
  

Main Activity

• Extend the idea to include dividing by other numbers, using props. Ask:what if we want to share this bag of 12 sweets between three children; or to divide 12 by 3? How many sweets does each person get? What if there are 4 people? Briefly do the inverse: so if 3 people each have 4 sweets, how many sweets altogether? (12.)

• Display the words to the song and ask children to follow them. Discuss what is happening in the story. Ask children to think about what happens when we share between (or divide by) more children – and ascertain that each person receives fewer pieces.

• Explain that although this is a song about sharing (dividing), children will be using it today to do the inverse – in other words, multiplying.

• Demonstrate that a 24-piece bar of chocolate could be set out as an array of 6 x 4 pieces. We can say, ‘Six lots of 4 is 24, or 6 x 4 = 24.’

• Ask children to think about other ways that the 24 pieces could be represented, still making a rectangle.  Ask for helpers to investigate at the front of the class, say how many lots of a number equals 24, and write out the number sentence.
  
  

Independent Activity

• Give out one laminated/card image of 24-piece chocolate bar (in 6 x 4 blocks) per pair, and one pupil whiteboard and dry-wipe marker each. Demonstrate once more that six lots of 4 is 24, and ask them to copy 6 x 4 = 24.

• Ask children to cut out the squares of chocolate and rearrange them into another rectangular grouping, then to write down the new number sentence. How many different calculations can they find?

• Repeat the exercise for different chocolate bars: 18- or 20-piece, for example, or ask children to create their own.
  
  

Differentiation – Support

• The Independent activity is made up of two components: arranging the chocolate into rectangles and writing out the number sentence.  The first is a somewhat challenging problem solving activity in its own right.  Provide support by scaffolding the second part, eg. ? x ? = 24.

• Use a 12-piece image of a bar of chocolate.

• For hearing impaired children who are proficient in the use of sign language, use the signed video on the Sing Up youtube channel.
  
  

Differentiation – Extension

• Write out the division calculations from the original as number sentences, eg. 24/4 = 6 and 24/5 = 4 r4.

• Investigate in pairs whether 6 x 4 = 24 is different to 4 x 6 = 24?  Does it depend on the context?
  
  

Plenary

• Play the first four verses of the song again and ask children to join in. During verses 2-4, write out the calculation on the board as a divide, eg. 24 x 2 = 12.
  
  

AfL

• Ask children to do the inverse of each divide, eg. 12 x 2 = 24.

• Give other multiply/divide number sentences and ask for the inverse calculations.

• In groups, write verses for the song where the bar of chocolate is made up of 32 pieces.
  
  

Next steps

• Dividing where the answer gives a remainder.  Use verse 5 (24/5 = 4 r4) as a starting-point.
  
  

Differentiated success criteria

All children will:

• Be able to work out simple multiplication facts from know division facts, and vice versa.

• Find different multiplication calculations to make a given number.

Some children will:

• Be able, without using visual aids, to work out multiplication facts from know division facts, and vice versa.

• Find different multiplication calculations to make a given number, and invert these to make a division calculation.

A few children will:

• Create and solve their own problems based on the inverse relationship between multiplication and division.

• Calculate divisions which leave a remainder.