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Learning about maths in Year 3. Place value Addition, subtraction Multiplication & division. Autumn term 2010. Place Value. Understanding the value of numbers. How Many?. Hundreds. Tens. Ones. 100. 10. 4. 114. 100 + 10 + 4=. How Many?. Hundreds. Tens. Ones. 300. 30.
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Learning about maths in Year 3 • Place value • Addition, subtraction • Multiplication & division Autumn term 2010
Place Value Understanding the value of numbers.
How Many? Hundreds Tens Ones 100 10 4 114 100 + 10 + 4=
How Many? Hundreds Tens Ones 300 30 300 + 30= 330
Thousands Tens Ones Hundreds 1000 200 40 3 1000 + 200 + 40 + 3= 1,243
Thousands Tens Ones Hundreds 2000 300 20 5 2000 + 300 + 20 + 5= 2,325
Mental Maths Activity We are going to practise adding numbers to 20. Try this calculation. + 7 9
9 10 11 12 13 14 15 16 9 + 7 We can do this by counting on. We have counted on 7.
What strategies would you use to add 2 two-digit numbers quickly? • This is one way to do it. • Split (partition) the tens. • Split (partition) the units. • Count on.
64 + 32 = 96 Split the tens. Split the units. 60 + 30 + 4 + 2 = 96 Count on. 60 + 30 = 90 4 + 2 = 6 90 + 6 = 96
Practise subtraction facts to 20. subtraction take away
19-10 15 - 6 18 minus 9 5 less than 12 16 subtract 8
Subtractions using number lines. Top Tip! Don’t forget to count on to the nearest multiple of 10.
36 – 24 = 12 6 6 24 30 36 Where shall we jump to first? Now we can jump to 36. How many have we counted on altogether? 6 + 6 = 12
19 45 – 26 = 4 10 5 30 40 26 45 Where shall we jump to first? Now where shall we jump? How many from 40 to 45? 4 + 10 + 5 = 19
45 – 19 = Can you think of a quick way to do this? 19 is near to 20. 45 – 20 = 25 25 + 1 =26
Year 3 Derive and recall multiplication facts for the 2, 3, 4, 5, 6 and 10 times-tables and the corresponding division facts. Year 4 Derive and recall multiplication facts up to 10 × 10, the corresponding division facts. Year 5 Recall quickly multiplication facts up to 10 x 10 and derive quickly corresponding division facts. Year 6 Use knowledge of place value and multiplication facts to 10 × 10 to derive related multiplication and division facts involving decimals (e.g. 0.8 × 7, 4.8 ÷ 6). Use knowledge of multiplication facts to derive quickly squares of numbers to 12×12. Learning times tables www.teachingtables.co.uk
Division Understanding division as sharing and grouping. To know what to do with remainders. 15 3 = ? We can solve this by jumping along a number line.
15 3 = 0 3 We jump along in 3s – we use our 3 times tables.
15 3 = 0 3 6
15 3 = 0 3 6 9
15 3 = 0 3 6 9 12
15 3 = 0 3 6 9 12 15
15 3 = 0 3 6 9 12 15 How many jumps have you made?
How many jumps have you made? 5 0 3 6 9 12 15 So 15 3 = 5
+ 1 0 4 8 12 16 17
+ 1 0 4 8 12 16 17 So 17 4 = 4r1
Try to solve these real life problems using the method we have just used. David Beckham has 24 trophies. He puts 4 on every shelf. How many shelves can he fill?
What about 24 4? 0 4 8
What about 24 4? 0 4 8 12
What about 24 4? 0 4 8 12 16
What about 24 4? 0 4 8 12 16 20
0 4 8 12 16 20 24 24 4 = 6 Beckham would need 6 shelves for his trophies.
http://www.st-john.leicester.sch.uk/ Learning about maths in Year 3 1st Tonight’s power point saved here 2nd