National curriculum content
- Add and subtract numbers mentally, including:
- A three-digit number and ones
- A three-digit number and tens
- A three-digit number and hundreds
- Add and subtract numbers with up to three digits, using formal written methods of columnar addition and subtraction
- Estimate the answer to a calculation and use inverse operations to check answers
- Solve problems, including missing number problems, using number facts, place value, and more complex addition and subtraction
- Add and subtract multiples of 100
- Add and subtract 1s
- Add and subtract 3-digit and 1-digit numbers - not crossing 10
- Add a 2-digit and 1-digit number - crossing 10
- Add 3-digit and 1-digit numbers - crossing 10
- Subtract a 1-digit number from 2-digits - crossing 10
- Subtract a 1-digit number from a 3-digit number - crossing 10
- Add and subtract 3-digit and 2-digit numbers - not crossing 100
- Add 3-digit and 2-digit numbers - crossing 100
- Subtract a 2-digit number from a 3-digit number - crossing 100
- Add and subtract 100s
- Spot the pattern
- Add two-digit numbers - crossing 10
- Subtract a 2-digit number from a 2-digit number - crossing 10
- Mixed addition and subtraction problems
- Add and subtract 2-digit and 3-digit numbers - not crossing 10 or 100
- Add 2-digit and 3-digit numbers – crossing 10 or 100
- Subtract a 2-digit number from a 3-digit numbers – crossing 10 or 100
- Add two 3-digit numbers – not crossing 10 or 100
- Add two 3-diit numbers – crossing 10 or 100
- Subtract a 3-digit number from a 3-digit number – no exchange
- Subtract a 3-digit number from a 3-digit number – exchange
- Estimate answers to calculations
- Check answers
What we want children to know
- Recognise patterns when we add and subtract 1, 10 and 100
- Know and understand place value and that ten ones are the same as one ten
- Learn that we can only hold single digits in each column, anything over must be exchanged
- Partition two-digit numbers in order to add and subtract from them
- Show addition and subtraction using different representations such as Base 10, arrows cards and place value charts
- Use their knowledge of inverse to work out missing number problems
- Use the column method, when appropriate, to solve addition and subtraction calculations
- Develop flexibility and be able to select the most effective method
- Check how reasonable their answers are and refer to ‘near numbers’
- Explore ways of checking to see if an answer is reasonable
What skills we want children to develop
Use knowledge to solve Reasoning and Problem Solving questions such as:
True or False?
Are these number sentences true or false?
E.g. 597 _ 7 = 614 804 – 70 = 744 768 + 140 = 909
Explain your reasons.
_ _ + _ _ + _ _
The total is 201. Each missing digit is either a 9 or a 1. Write in the missing digits.
Is there only one way of doing this or lots of ways? Convince me.
Always, Sometimes, Never:
Is it always, sometimes, never true that if you subtract a multiple of 10 from any number the ones digit of that number stays the same.
- How many different ways can you represent 200 + 300?
- Using Base 10, can you partition your numbers?
- How many tens can we add to 352 without exchanging?
- How many ones do we need to exchange for one ten?
- What do you notice when we add and subtract 100s from a 3-digit number?
- Do we need to write a zero in the hundreds column when there are no hundreds left?
- Can you draw a picture of this representation?