‘I didn’t learn to do it that way!’

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‘I didn’t learn to do it that way!’ - PowerPoint PPT Presentation

Beaconside Parents’ Maths Workshop – Addition and Subtraction 5 th March 2013. ‘I didn’t learn to do it that way!’. Maths! What’s your experience?. What are your first thoughts? Do you panic? Have you any negative experiences?. A world without numbers!. Be positive about number!.

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Presentation Transcript

5th March 2013

‘I didn’t learn to do it that way!’

• What are your first thoughts?
• Do you panic?
• Have you any negative experiences?
A world without numbers!

Children learn + and - by:
• Being confident about number – seeing that numbers are everywhere.
• Using and experiencing a range of resources.
• Using and experiencing a range of methodsso that they can decide which is the best method to use:

Pictures; mental calculation - with or without jottings; structured recording; calculator

How ?

• Understanding and using a selection of mental strategies
• Knowing number bonds ( ie 7+3=10, 18+2= 20)
• Place value ( understanding the order and the value of digits including zero as the place holder)
• Money ( everyday money- calculating change)
• Problem solving
Resources
• Number line
• Counters
• Online games
• Place value cards
• Unifix sticks
• Number square
• Subitising activities
Subitising
• Subitising is the ability to recognise dot arrangements in different patterns without counting.
• It is a fundamental skill in the development of number sense and will help in the ability to add and subtract as well as recall number bonds quickly.
• We can learn:
• there are 5 dots.
• 5 is more than 4
• 5 objects can be separated in to a set of 2 and 3
• 5 counters, no matter how arranged, still retain the same numerical quantity
• The oral name for a set of 5 things is ‘five’
Subitising: Activity 1

Play – show me (digits and numbers)

Fantastic for fast recall of number bonds – support with + and – facts without the need for counting.

Place Value – Activity 2
• We use place value cards in combination with unifix cubes and 100 squares to recognise values of numbers.

i.e. Use the place value cards to make the number 245

Partition the number.

Children understand 245 =

200+40+5 =245

Zero is important- it is the place

Holder and keeps the number in the

Correct column.

Activity 3 –addition with jottings using partitioning
• 25 + 33= 58
• Success Criteria:
• Step 1: partition numbers ( tens 20 + 30) (units 5+3)
• Step 2: add up the Tens ( 20 + 30 = 50)
• Step 3: add up the Units ( 5+ 3 = 8)
• Step 4: add both (50 + 8= 58)
• 55 + 26 ( 50 + 20= 70) ( 5+6= 11)
• 70 + 11 = 81
• Key skills – adding 10s mentally – can you use a number square to spot patterns when adding multiples of 10 to any number?
Activity 4: Back to number bonds:
• 1+9 = 10 and 9+1=10
• 10+90 = 100 and 90+10 = 100
• 100+900 = 1000 and 900+100=1000
• 0.1 +0.9 = 1 and 0.9+0.1 = 1
• Look for the patterns. Let the children discuss.
• Now have a go! Show me!
• See the relationship between subtraction and addition
• 10–9 = 1
• 10-1 = 9
• Now have a go! Show me!
• Subtraction is count back
• Subtraction = difference
• Subtraction = less than
• NUMBER LINES:
• They show the order of numbers from left to right.
• They are used to count on and back in 1s (Nursery+)
• Counts on and back in 1s, 2s, 5s, 10s (Reception and Year 1+)
• Count on and back in 100s (Year 2/Year 3+)
• Count on and back in 1000s(Year 4+)
• Count on and back in decimals/fractions (Year 5+)

Activity 6 - Have a go…

Children will begin to use their knowledge of partitioning and counting on in larger steps as they become more confident.

Have a go with a partner.

Number lines (Subtraction):

Starting in Reception/Year 1

They use number lines by counting back from the start number.

The number line should also be used to show that 6 - 3 means the ‘difference between 6 and 3’ or ‘the difference between 3 and 6’ and how many jumps they are apart.

Empty Number lines (Subtraction):
• ‘Finding the difference method’ – Counting on (Y2 –Y6)
• Success criteria
• Put the smallest number on the left
• Put the largest number on the right
• Subtract by finding the difference and counting on in steps you feel comfortable.
• Example:

Have a go!

Now on to the formal methods…