Normally as we approach the end of June in class we revise areas of learning with the children and make assessments. Over the last number of weeks you will have become increasingly aware of your child and their strengths and areas for development. This is a fantastic position for you to be in as we head into the summer holidays. You will understand where you child would benefit from continued work over the summer (if you feel necessary) .
Mental Maths Revision
You will notice we have skipped forward a few pages in the subtraction booklet this week. Linking addition and subtraction facts is the last new concept for P2. We feel it is important to address this concept before the end of this school year so the children are familiar with it. We hope you find the explanations beneficial,
Relationship between addition and subtraction
Begin by watching the linked video on the relationship between addition and subtraction (This clip is on YouTube so just be mindful about advertising and programmes following this linked video). When posed with a subtraction math fact, the most efficient way to solve it is by knowing the related addition fact. When the recall of addition facts is automatic and students understand the connection between addition and subtraction facts, their fluency with subtraction facts naturally increases.
Inverse Relationship Between Addition and Subtraction
A number fact is made up of three numbers. These three numbers can be used to make up other number facts. Knowing one fact can help children with other facts. Look at the number facts we can make with the numbers 3, 4, and 7.
3 + 4 = 7
7 – 3 = 4
4 + 3 = 7
7 – 4 = 3
Generally, subtraction facts are harder for children to learn than addition facts. If a child knows that 6 + 9 = 15, and he or she sees the subtraction sentence 15 – 9 = __, the child can think, 9 and what are 15? This use of thinking of the related addition fact when children encounter a subtraction fact they don't know should be encouraged. Children often find themselves either counting up or counting back to solve subtraction, and that is inefficient. If children learn the important inverse relationship between addition and subtraction, subtraction facts will become much easier. As you work with the children, use questions that encourage this strategy of the inverse relationship between addition and subtraction.
Begin your instruction by reviewing with children the related addition facts. Write 2 + 3 = 5 and 3 + 2 = 5 on a page. Ask children what they can tell you about these two addition facts. Explain that the numbers 2 and 3 are in both facts, but they are reversed. Also, the two facts have the same three numbers.
Then tell children that they are going to learn something new called a fact family. Explain that it is not a real family, but that the facts are related like people are related, therefore they have been given the name family. Point to the two addition facts that you wrote on the board and say, "Now I am going to write two related facts." Write 5 – 2 = 3 and 5 – 3 = 2 on a page. Ask, "Do you see anything the same about these two facts and the two addition facts?" Point out that they use the same numbers. "Do you see anything different about these two facts and the two addition facts?" Children should respond that the new facts are subtraction facts and the largest number comes first in both facts. Tell children that these four facts make up a fact family.
Take time to discuss other fact families with children. Then write 3 + 3 = 6 on a page. Ask if it has another addition fact. Explain that it does not because 3 + 3 turned around would be 3 + 3. Ask if any child can tell you what the related subtraction fact might be. (6 – 3 = 3) Discuss other doubles and why there is only one addition and one subtraction fact in fact families that have doubles.
Ask children why they think that it is important to learn fact families. Explain that once they know one fact, that fact can help them find out the rest of the facts in the family. Tell children that they are now going to learn a lot more fact families.
Activity 1 Complete page 31 and 32 in Subtraction booklet Linking addition and subtraction
Activity 2 Complete one or more of the Number family activities linked below.
Tens and ones
Begin by watching the short video clip about tens and ones linked underneath (This clip is on YouTube so just be mindful about advertising and programmes following this linked video).
Usually in class we would do lots of practical work before written activities. Such as…
*Tens and ones matching cards (attached)
*arrow cards (attached) to build numbers
*base ten and ones - you could use stick of 10 lego cubes to make a ten and single cubes for ones
We would ask the children to complete several tasks using the cards and cubes.
Show me 15
Show me the number after/ before/ between
You could also set out different numbers using the arrow cards and ask the children what number you have made.
How many tens are there in this number?
How many ones are there in this number?
Through doing this the children will manipulate the cubes and number cards to find the appropriate number. This helps to show the children practically how many tens and ones there are in a number.
Before beginning each of these activities use the arrow cards and cubes to build numbers as mentioned.
Activity 3 Cut and stick Tens and ones
Activity 4 How many tens and ones?
Activity 5 Eggs tens and ones (Use arrow cards to help if needed)