Year 3 Teaching Sequence 12 - Ordering and finding fractions of shapes and numbers (three days) Prerequisites: Know doubles to double 20 by heart (see oral and mental starter bank 12) Overview of progression: Children fold paper in half and half again to find ¼, ½ and ¾ of shapes and see the equivalence between two quarters and one half. They do the same with paper strips of objects to find ½, ¼, and ¾ of numbers (all multiples of 4) and then half of odd and even numbers to 30 using strips or cubes to help. Children then move onto finding thirds and two thirds of shapes, and one third of multiples of 3 by folding strips as for quarters. Note that children will probably find folding the strips of objects into thirds more difficult but reminding them that each part must have the same number of objects should help to overcome some inaccurate folding. Watch out for children who do not realise that fractions are equal parts, and so for example divide a shape into three or four parts, but not equal parts. This is not surprising as we use the fraction words inexactly in everyday language: “Give your cousin the larger half!” © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y3 Maths TS12 – Aut – 3days Objectives: Understand and use fraction notation Find ½, ¼, ¾, 1/3 and 2/3 of shapes, strips of objects and numbered strips Recognise equivalence between ½ and 2/4 by folding shapes and using diagrams Find half of odd and even numbers to 40, using notation such as 13½ Whole class Group activities Paired/indiv practice Resources Give each child a rectangular sheet of paper. Ask them to fold it in half in a different way to their maths partner. What’s special about each half? How do we write one half? Fold it into four equal parts; try to do this in a different way to your partner. What do we call each part? How do we write one quarter? Collect in a few differently folded sheets of paper (e.g. diagonal folds), and quickly shade ¾ of each one. How much is shaded? And on this one? How do you know? Show me one half of your sheet of paper. What do you notice? Discuss how one half is the same as two quarters. Give chn strips of 8 objects (see resources). Fold your strip in half. How many in each half? Now fold it in half again, so you have four equal parts. What do we call these? How many in each quarter? How many in two quarters? What do you notice? Discuss how two quarters have the same quantity as one half. How many in three quarters? Together write sentences about fractions of objects of the strip: ½ of 8 is 4 ¼ of 8 is 2 2/4 of 8 is 4 ¾ of 8 is 6. Rpt with a strip of 16 objects, asking chn to work in pairs to write their own sentences on their whiteboards. Group of 4-5 children Give each pair six strips of objects (see resources). I’m thinking of one of your strips. I fold it in half, and see ten objects in each half. Which strip do you think I’m thinking of? I’m thinking of one of your strips. I fold it into quarters and can see four objects in each quarter. Which strip do you think I'm thinking of? Fold it in quarters to check. Repeat with other strips. Easier: Focus more on halves to begin with. Ask chn to fold each strip into quarters before describing quarters. Harder: Also include descriptions such as I can see 15 objects on three quarters of the strip. Give each pair of chn strips of objects, which they fold in half to find ½, ¼, 2/4, and ¾ of numbers (all multiples of 4). They write sentences about halves and quarters as in the whole class teaching. Harder: Challenge chn also to work in pairs to halve 10, and then find a quarter of ten. A4 paper Activity sheets of strips of 8 objects and 16 objects Activity sheet of six strips of objects (see resources) © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y3 Maths TS12 – Aut – 3days Give each child a strip of seven objects (see resources). Fold the strip in half to find half of seven. Take feedback about what happens. Agree that there are three objects in each half and one split down the middle, so 3 and a half in each half. Write ½ of 7 is 3 ½ on the board. Give each pair of chn 26 cubes and ask them to make a tower. Break the tower in half to find half of 26. Agree that half of 26 is 13 and record the on the board. What is half of 20? And half of 6? Record Half of 26 20 6 10 3 10 + 3 = 13 What is double 13? What is double 10? Double 3? So double 13 is 26. What do you think half of 27 might be? Talk to your partner. Take feedback and discuss that 27 is one more than 26, and so there would be one more cube to split between the two groups giving and answer of 13½. Also discuss that half of 20 is 10 and they agreed earlier that half of 7 is 3½, so half of 27 is 13½. Half of 27 Group of 4-5 children Give each pair strips of objects from the activity sheet (see resources). I’m thinking of one of your strips. I fold it in half, and see five objects in each half. Which strip do you think I’m thinking of? I’m thinking of one of your strips. I fold it in half, and see five and a half objects in each half. Which strip do you think I’m thinking of? Repeat with other strips. Easier: Use the first six strips from the easier version of the Activity sheet. Chn work in pairs to draw lines to show how to cut strips of objects in half. They then use cubes to help them to find half of each number from 20 to 30. Discuss what they have found out about halving odd and even numbers in the plenary. Easier: Chn work in pairs to cut strips of objects in half (see resources). Harder: Chn work in pairs to find of half of each number from 20 to 40. They use cubes to help where necessary. Strips of seven objects (see resources) Strip of 15 objects (see resources) Activity sheets of strips of objects 20 7 10 3½ 10 + 3½ = 13½ Work with a partner to find half of 15. Use your cubes to help. Agree that half of 14 is 7, and if they were to cut the remaining cube in half, they would have 7½ cubes in each half. © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y3 Maths TS12 – Aut – 3days Show a strip of 15 objects on the board (see resources). If you were to cut this strip of objects in half, where would you cut it? Ask a child to come up and draw a line to show you. Is there the same amount on each side of the line? Give each child a rectangular sheet of paper. I want you to fold it into three equal parts; this is a bit more difficult than folding into two or four! Share examples of chn’s folded rectangles (some may have folded horizontally, and some vertically), say that we call each part a third and stress the importance of each part being of equal size. Write 1/3 on each of three parts of one rectangle. Draw a square on your whiteboards, and divide it into thirds. Repeat with a circle, if necessary showing how to divide like a cake, and finally a regular hexagon. Share different ways of doing this. Sketch oblongs, squares, circles and hexagons on the board, and shade one or two thirds. Ask chn how much is shaded in each case, showing how to record 2/3. Ask chn to draw two smiley faces on each third of their paper rectangles. How many smiley faces altogether? What is 1/3 of 6? What number sentence can we write? Draw another two smiley faces on each third. How many faces altogether? What fraction number sentence could we write? Group of 4-5 children Give each pair six strips of objects (see resources). I’m thinking of one of your strips. I fold it into thirds, and see three objects in each third. Which strip do you think I’m thinking of? I’m thinking of one of your strips. I fold it into thirds and can see four objects in each third. Which strip do you think I'm thinking of? Fold it in thirds to check. Repeat with other strips. Easier: Ask chn to fold each strip into thirds before describing thirds. Harder: Also include descriptions such as I can see 10 objects on two thirds of the strip. Give each pair of chn strips of paper, which they fold into thirds. They draw the same amount of simple objects on each third and write sentences about them as in the whole class teaching. Easier: Draw one, then two, then three… five objects on each third of the strips. Harder: After drawing five strips ask chn to discuss what might be one third of 30 and 300! © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. A4 paper Strips of paper Activity sheet of six strips of objects (see resources) Y3 Maths TS12 – Aut – 3days