Schoolsweb
Listen

Link to the DfCFS home page
The Standards Site - Raising Standards

This website is changing: Find out more.

Year 3 Block A - Counting, partitioning and calculating Unit 3

Objectives

Children's learning outcomes are emphasised
Assessment for learning
  • Solve one-step and two-step problems involving numbers, money or measures, including time, choosing and carrying out appropriate calculations

    I can solve a problem by writing down what calculation I should do

Tell me how to start to solve this problem.

I think of a number and add 12 to it. My total is 38. What is my number?

Show me how to solve the problem using an empty number line, or a 100-square. Write down the calculation that you would do.

Show me how to solve this problem using an empty number line.

Ling got into the swimming pool at 10:30. She got out at 11:20. How long was she in the pool?

What is the answer to 20÷5? Can you make up a problem that means you need to work out 20÷5 to solve it?
Write down the calculations that you need to do to solve this problem.
Three buns cost 24 pence. What do two buns cost?

  • Round two-digit or three-digit numbers to the nearest 10 or 100 and give estimates for their sums and differences

    I can use rounding to estimate a sum or difference

There are enough pencils in this box for each child in the class to have one each. Approximately how many pencils is that? How many pencils would you estimate we would need for 10 classes?

To the nearest 100, there are 400 children in a school. How many children could there be in the school?
Explain your answer. Could there be 450 children? Could there be fewer than 350 children?

Estimate the answers to these calculations: 167plus86, 409minus177. How did you work out your estimate?

  • Add or subtract mentally combinations of one-digit and two-digit numbers

    I can find the sum of or difference between one-digit and two-digit numbers in my head (e.g. 7plus45, 45minus7)

    I can add several one-digit numbers in my head

Here are some calculations: 52minus9, 8plus74, 71minus68, 4plus5plus6minus8. What strategies did you use to work out the answers? Could you use a different method?

How could you check that your answer is correct?

Do this calculation in your head: 12minus11plus10minus9. How did you do it? Use this method to work out 13minus12plus11minus10. Now work out 22minus21plus20minus9 and 82minus81plus80minus79. Write down another calculation that you could work out quickly in this way.

  • Develop and use written methods to record, support or explain addition and subtraction of two-digit and three-digit numbers

    I can add and subtract numbers using an empty number line
    I can add and subtract numbers by writing one number under the other and using partitioning

Show me how you use counting up on an empty number line to work out 236plus75 and 236minus75. Which number did you start with? What are the important landmark numbers to use? [multiples of 10 or 100]

What are the sizes of the steps? Can you show me another way you could do this on the number line?

Here are two numbers: 654 and 148. Partition 148. What is the answer when you add 8 units to 654? Now add the 40. Now add the 100. How will you record this? What is the answer? Show me this method for two other numbers.

Here are two numbers, 514 and 136. Partition 136. What is the answer when you subtract the 6 units from 514? How will you record this? Now subtract the 30. Now subtract the 100. What is the answer? Can you use this method to subtract 263 from 514?

  • Derive and recall multiplication facts for the 2, 3, 4, 5, 6 and 10 times-tables and the corresponding division facts; recognise multiples of 2, 5 or 10 up to 1000

    I can use my tables for 2, 3, 4, 5, 6 and 10 to work out division facts

Count back in fours from 32 to 0. How many fours did you count? Show me hops of 4 back from 32 on the number line.

What is the missing number in this statement: square ×5 equals35? How do you know?

Look at this statement: circle × square equals 35. What could the missing numbers be?
I know that 4×7 equals 28, so what is 28÷4?

Can you tell me some numbers that will divide exactly by 2? By 5? By 10? How do you know?

Which of these numbers are multiples of 2? How do you know?
18, 25, 40, 65, 120, 375, 468, 700

Which are multiples of 5? Multiples of 10? How do you know?

  • Use practical and informal written methods to multiply and divide two-digit numbers (e.g. 13×3, 50÷4); round remainders up or down, depending on the context

    I can use the tables facts that I know to work out division facts
    I can multiply or divide a two-digit number by a one-digit number
    If there is a remainder when I divide, I can work out whether to round the answer up or down

What is 4×2? What is 10×2? How could we use these facts to work out 14×2?

Tell me two multiplication facts we could use to work out 16×2. What is the answer?

What is 20÷2? What is 6÷2? How could we use these facts to work out 26÷2?

Tell me two division facts we could use to work out 28÷2. What is the answer?

What is 70÷5? Here are 72 cubes. Put them into groups of five. How many groups have you made?
How many are left over?

If you put the 72 cubes into boxes that hold five cubes, how many boxes would you need? Explain why.

If you put the 72 cubes in rows of five, how many rows could you make? Explain why.

  • Actively include and respond to all members of the group

    I can explain my solutions and methods to everyone in a group

What do you think of Asif's method of doing that calculation? Is it quicker or slower than your method? Is it easier or more difficult than your method? Why?

Tell everyone about the method you used. Explain to the group why you chose that method to use.

Learning overview

Children consolidate their counting on and back in steps of 2, 3, 4, 5, 6 and 10. They recognise when the numbers in a counting sequence are odd or even. For example, counting in steps of 4 from 3 will generate odd numbers only, while counting in steps of 3 from 4 the numbers alternate between odd and even. Children count in steps of two-digit numbers such as in 12s from 3, using a 10 and 2 count to generate 3, 13, 15, 25, 27, 37, 39, 49, 51... alternately whispering quietly and shouting aloud the numbers involved.

This offers an opportunity to assess children's understanding of numbers and the number system and their ability to recognise a wide range of sequences by asking questions such as how they know if any number is or is not in a particular sequence. For example:

If I start with 3 and count in 2s, will 21 be in the sequence?

Hayley makes a sequence of numbers. Her rule is: 'Find half the last number then add 10'. Write in the next two numbers in her sequence. 36, 28, 24, square, square

Look for children being able to recognise multiples of 2, 5 and 10.

Children solve problems and puzzles involving all four operations. They identify relevant information and select the appropriate operations in order to solve word problems such as:

There are 12 stamps in a sheet. Each stamp costs 28p. I buy a quarter of the sheet. How many stamps is this?

I pour out 180 ml and then 270 ml from a one-litre bottle of squash. How much is left?

This offers an opportunity to assess problem solving and the ability to select the mathematics that needs to be used in a range of classroom activities by asking children what resources they could use to model the problem and what method they would use to solve the problem. It also allows the opportunity to assess the ability to solve numerical problems, including those that have two steps, by asking children how they are interpreting the language of the problem to identify the steps that they need to take.

Children use counting strategies and partitioning to add and subtract combinations of one-digit and two-digit numbers. They add two-digit numbers by partitioning one or both of the numbers. For example, they work out 58 + 74 by partitioning 58 into 50 and 8 then adding 50 and 8 onto 74. Children use a similar strategy for subtraction, for example working out 94 - 58 or 294 - 58 by partitioning 58 and subtracting 50 then 8. They use counting-up strategies where appropriate, as in 124 - 68 where they count up from 68 to 70 to 100 to 124, recording and adding the steps 2, 30 and 24. Children use a number line to note the steps and to explain how they did the calculation. Children also subtract by counting on from the smaller to the larger number in their heads when the difference is small, as in 305 - 297, making notes to support calculation.

This offers an opportunity to assess mental methods and the ability of children to add and subtract two-digit numbers mentally by asking children how they are solving calculations mentally. In particular, look for children being able to make decisions about whether to partition numbers or to count up.

Children develop their use of the empty number line to support their calculations. They begin to record vertically addition and subtraction calculations that cannot be easily done mentally. They partition one of the numbers and add or subtract the units, tens and hundreds separately:

76+47

THIS IMAGE REQUIRES ALT TEXT

267-149

THIS IMAGE REQUIRES ALT TEXT

Children recognise the relationship between the vertical presentation and the steps on the number line. They begin to use an expanded layout that underpins the standard written method. For example, for 76 + 47 and 83 - 48 children use:

THIS IMAGE REQUIRES ALT TEXT

 

THIS IMAGE REQUIRES ALT TEXT

This offers an opportunity to assess the ability to add and subtract three-digit numbers using a written method by asking children to explain their written method. Look for children being able to add and subtract three-digit numbers both with and without bridging.Children round two-digit and three-digit numbers to the nearest 10 and 100 and use this to give approximate answers to addition and subtraction calculations. For example, they recognise that the answer to 247 + 76 will be just less than 250 + 80 or 330, and 183 - 48 is about 180 - 50 or 130. They understand that finding an approximate answer is a useful strategy for checking a calculation.

This offers an opportunity to assess children's understanding of the number system by asking children to demonstrate using a number line how they are making decisions to round up or down, or using examples such as 'Estimate the number marked by the arrow'.

THIS IMAGE REQUIRES ALT TEXT

In particular, look for children being able to order numbers up to 1000 and justify their answers through an understanding of place value.Children begin to work systematically, using lists or tables to organise their solutions to problems such as:

  • A farmer has cows and chickens on the farm. Altogether the animals have 24 legs. How many cows and chickens could there be on the farm?

Using problems such as these gives the opportunity to assess children's ability to communicate their mathematics, and in particular to show how they are looking to develop organised approaches to recording their work.

Children use their understanding of place value to support multiplication and division involving multiples of 10 to answer questions such as:

  • Three pencils cost 90p altogether. How much does each pencil cost?
  • Rani picks up seven 50 g weights. How much do these weigh altogether?
  • Sam is making cards. Each card takes 20 minutes. He starts at 4:30 and makes four cards. What time does he finish?

Children begin to use partitioning to multiply and divide two-digit numbers. For example, they calculate 24 × 4 by partitioning 24 into 20 and 4 and working out 20 × 4 + 4 × 4, and 96 ÷ 3 by partitioning 96 into 90 and 6 and dividing each part by 3 to get the answer 32. They identify remainders in related calculations such as 95 ÷ 3, and begin to round the remainder up or down when the context demands it. For example, if cars can each transport up to 4 people, they work out that 12 people would need 3 cars but 13 people require 4 cars.

This offers an opportunity to assess written methods. In particular, look for children being able to multiply and divide two-digit numbers by 2, 3, 4 or 5.Children solve problems such as:

  • Use three of the digits 2, 3, 4, 5 and 6 to create multiplication calculations (e.g. 34 × 6). What products can you make? What is the largest/smallest product?

They work in pairs or groups, with all children in the group contributing to decisions about the methods they use, whether they will use resources and how they will record their work.

This offers an opportunity to assess children's ability to discuss their mathematical thinking and begin to explain their thinking. In particular, look for children being able to make general statements such as saying where the largest, middle and smallest digits go when making the largest product above.


Resource links to existing published material

Mathematical challenges for able pupils Key Stages 1 and 2

Activities

PDF 923KB

Activity 35 - Duck ponds


Intervention programmes

Objectives for Springboard intervention unit

Springboard unit

Choose and use appropriate operations and calculation strategies to solve problems

Springboard 3 Unit 8 sessions 1 and 2 (PDF 154KB)

Explain how a problem was solved orally and, where appropriate, in writing

Springboard 3 Unit 10 sessions 1 and 2 (PDF 172KB)

Supporting children with gaps in their mathematical understanding (Wave 3)

Diagnostic focus

Resource

Does not make sensible decisions about when to use calculations laid out in columns

3 Y4plus/-
DfES 1130-2005 (PDF 101KB)

Has difficulty with adding three numbers in a column, except by adding the first two and then the last one

4 Y4plus/-
DfES 1131-2005 (PDF 95KB)

Click here for information on different file formats and their usage.

Wave 3 addition and subtraction tracking children's learning charts

PDF 161KB RTF 930KB Word 315KB

Wave 3 multiplication and division tracking children's learning charts

PDF 195KB RTF 1.3MB Word 430KB

Wave 3 Resource sheets and index of games booklet

PDF 500KB
Disclaimer notice
The Department for Children, Schools and Families wishes to make clear that the Department and its agents accept no responsibility for the actual content of any materials suggested as information sources in this document, whether these are in the form of printed publications or on a website. In these materials icons, logos, software products and websites are used for contextual and practical reasons. Their use should not be interpreted as an endorsement of particular companies or their products. The websites referred to in these materials existed at the time of going to print. Tutors should check all website references carefully to see if they have changed and substitute other references where appropriate.