Year 5 Teaching Sequence Summer 1 - Ordering negative and positive numbers (three days) Prerequisites: Use negative numbers in context, e.g. temperature (see Year 4 spring teaching sequence 7 and oral and mental starter bank 1) Count on and back in steps of constant size, e.g. 25, including beyond zero to -100 for example (see Year 4 summer teaching sequence 7 and oral and mental starter bank 1) Overview of progression: Children compare temperatures (above and below zero degrees Celsius) and calculate rises and falls in temperature. They order pairs of negative and positive numbers and then count on and back in steps of constant size including through zero. Note that the vertical scale of the thermometer is used as a context for negative numbers, and so negative numbers out of context are shown on a vertical scale to start with to link with this image. Later we switch to a horizontal scale. Children need to understand that both ‘minus’ and ‘negative’ are used to describe these numbers. Watch out for children who think that temperatures such as -7°C are warmer than -3°C because 7 is higher than 3. © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y5 Maths TS1 – Sum – 3days Objectives: Count on and back in steps of a constant size, extending beyond zero Order negative and positive numbers on a number line and temperature scale Calculate a rise/fall in temperature Whole class Group activities Launch the ITP Thermometer, and choose a range of -10 to 10. At what sort of temperature might we get ice outside? Why? Agree that as water freezes at 0 degrees Celsius the temperature will be less than this, e.g. minus one, two. Ask chn to label some of these temperatures on the thermometer. Which of these temperatures is the coldest? During one day it was 5 degrees Celsius. During the night the temperature fell to minus 5 degrees Celsius. Move the slide to 5, then -5 on the thermometer. Group of 4-5 children Use an internet site to find temperatures in cities around the world (e.g. www.bbc.co.uk/weather) including countries where the temperature is below zero and record them on Postits™. Ask chn to put them in order from the warmest to the coldest. Find the cities on a globe. Ask questions such as: Which is colder, Reykjavik or Helsinki? What is the difference in temperature? Sketch a vertical number line to help. What happens to temperatures generally as you move further away from the equator? Why do you think this is? Easier:/Harder: Adapt your questions as appropriate, for example asking chn to find narrower or wider differences. How many degrees has the temperature fallen? How many degrees had it fallen when it got to zero? Draw a hop of 5 to 0. And then? Draw hop of 5 to -5. Click on change to check. Move the slider up to 3°C. The next day the temperature rose, but it was colder than the previous day. How much has the temperature gone up by? Draw a hop of 5 to 0°C, and then a hop of 3 to 3°C. Paired/indiv practice Chn order temperatures and calculate rises and falls in temperature (see resources). They sketch vertical lines to help if necessary. Easier: Chn are given a thermometer picture to help them work out falls in temperature. © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Resources ITP Thermometer Access to the internet Globe Activity sheets (see resources) Y5 Maths TS1 – Sum – 3days Repeat with similar questions. Close the ITP and display the following table: Maximum Minimum temperature temperature Monday 7°C -2°C Tuesday 5°C -3°C Wednesday 1°C -2°C Thursday 2°C -4°C Friday 0°C -5°C These are the temperatures recorded at a school weather station. When do you think they might have been recorded? What was the highest temperature recorded? And the lowest? On which day was there the greatest difference between maximum and minimum temperature? By how much did the temperature fall? Sketch a vertical line from -2°C to 7°C to help chn to see this. Which day has the smallest difference between maximum and minimum temperature? What was the drop? Sketch a vertical line to help chn see this. Show chn a counting stick so that it is vertical. Let's count back in ones from five. Start at the top end of the counting stick as chn see it. 5, 4, 3, 2, 1, 0, what comes next? Continue saying negative one, negative two… Remind chn that numbers less than zero are called negative numbers, and numbers more than zero are called positive numbers. When might we use negative numbers? Agree examples such as temperature, depth below sea level, and, especially, overdrafts. When we owe money, we talk about having negative or minus amounts of money. Point out that we often say ‘minus’ rather than ‘negative’. Write 0, -2 and -4 on Post-its™. Point to the top of the counting stick. If this is 5 and we count down in ones, Group of 4-5 children Write numbers from -20 to 20 on separate cards and shuffle them. Deal them face down to the children. Turn over a sand timer. Can everyone order their cards before the sand runs out? Reshuffle and repeat. Show me a card between -5 and 0. Show me a card less than -10. Show me a card greater than -6. Show me a card between -2 and 2. Repeat with similar questions. Easier: Give each pair a set of shuffled Give a set of -10 to 10 cards to each pair. They shuffle and then arrange them in order from -10 to 10. They reshuffle them, each select three cards and write them in order from the least to the greatest. Repeat. Easier: Chn practise ordering cards -10 to 10 several times. They then take a card and write down the number before © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Counting stick ITP Number Line -20 to 20 cards One minute sand timer -10 to 10 cards Y5 Maths TS1 – Sum – 3days where should we stick 0? And negative 2? And negative 4? Turn the counting stick so that it is horizontal. Point to the left, as chn see it. This is -5. We’re going to count from -5 to 5. Count on, speeding up as you pass zero, and then count back again. Ask chn to place the Post-its™ on the stick in the correct places. Launch the ITP Number Line and choose a range from -20 to 20. Click so that the numbers are not displayed on the tags and move them to -2 and -8. What numbers are labelled? How did you work it out? Which number is bigger? Record -2 > -8. Write a number in-between on your whiteboards. Repeat with other pairs of numbers including mixes of negative and positive numbers. Show chn the counting stick so that it is horizontal. Point to the left, as chn see it. This is -10. We’re going to count on in twos. Where do you think we will get to? Count on in twos, speeding up as you pass zero, and then count back again. Repeat, this time starting at -40 counting in fives, starting at -100 counting on in tens and finally starting at -200 and counting on in 25s. -5 to 5 cards and ask them to put them in order before the sand runs out. Ask similar questions when they have all their cards in order. it, the number on the card and the number after it. Group of 4-5 children Write numbers from -10 to 10 on separate cards and shuffle them. Ask chn to help you to put them in order. If we have 3 subtract 4, we’d normally say we can’t do it, but we can if we use negative numbers. What do you think 3 subtract 4 is? Count back 4 from 3 Give each pair a sheet of -20 to 20 number lines (see resources). They roll a dice and count back in steps of that size from 20 until they pass 20, recording each hop as they do so. E.g. they roll a 6 and count back in steps of 6: 20, © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Counting stick ITP Number Line -10 to 10 cards -20 to 20 number lines (see resources) 1-6 dice Y5 Maths TS1 – Sum – 3days Launch the ITP Number Line and choose a range from -20 to 20. This time we’re going to count back in 3s. Together count back in 3s, recording the jumps on the number line as you do so. Take particular care when crossing zero. Repeat, this time counting back in 6s. using the cards. Together make up other subtractions with a negative answer. Discuss situations in ‘real life’ where these sorts of subtractions are possible, e.g. falls in temperature, descending below sea level, and perhaps going overdrawn, although not to be recommended! Easier: Mark zero on the middle of the counting stick and use this vertically to support counting back through zero when subtracting. 14, 8, 2, -4, -10, -16, -22. If they roll one, they roll again. Easier: Chn count back in 2s, 4s, 5s and 10s from 20 to -20. © Original teaching sequence copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users. Y5 Maths TS1 – Sum – 3days