Maths focus: Doubling & Halving

Learning Intention:  

Know double means two of the same.

To get a double of a number, we add the same number to itself. For example, double 2 is 2 + 2 = 4. 

* Link doubling with addition.

Recognise, find and name a half as one of two equal parts of an object, shape or quantity

Key vocabulary: double/doubling  same number/amount    two lots of       twice   total   altogether makes

half/half of      halve    halving      split into 2 equal parts     1/2

Useful Websites

Doubling:

Double number zoo song- Click here: https://www.youtube.com/watch?v=e-KTHfrFit0   

Halving:

“Give me half”-  Click here : https://www.youtube.com/watch?v=hVaxiJB6Fls   

Explanation of halving-   Click here : https://www.youtube.com/watch?v=no79jMi8-w8   

Doubling & Halving:

Numberblocks: Double Trouble Series 2 (about doubling and halving numbers up to 8)- Click here : https://www.bbc.co.uk/iplayer/episode/b08q4jkq/numberblocks-series-2-double-trouble

Double and half of a number- Click here: https://www.youtube.com/watch?v=oCBbRXbbDsg  

Explanation of doubling & halving- Click here: https://www.youtube.com/watch?v=8gbTD8rJhXA 

Below are some activities you can do over the course of the week.

You can do one or a few each day. You can also repeat activities in order to help your child to fully understand the concepts of doubling & halving, or if your child has particularly enjoyed them.

Doubling

Activity:

Explain to your child that a double means two of the same amount/number added together.

Play a game of SNAP- use numbered cards or write 4 sets of numbers on pieces of paper (0 to 10). Shuffle/ mix up the numbers. Ask your child to share the cards/ pieces of paper between the number of people playing the game (minimum of 2). Then take it in turns to turn over the numbers in their pile and when two of the same number are turned over in succession, the first person to shout “SNAP” and say it is a double because the two numbers are the same, wins the pile of numbers. The winner is the only person left with cards.

Activity:

Using a plate and a selection of items found around your home (e.g. counters, pebbles, cars, pasta shapes etc.) Ask your child to put 2 items onto the plate, then ask him/her to double that number (your child will add 2 more items). Provide a prompt if your child needs one. Then say, “Double 2 is 4…….2 add 2 makes 4.”

Repeat with numbers up to 5, and if your child is ready, move onto numbers up to 10.

Encourage your child to explain what s/he has done, using the correct language, e.g. “Double 4 is 8……..4 add 4 makes 8 altogether.”

Ask your child how s/he could record the doubling calculation. Your child might choose to represent the amounts using pictures, some may choose to write it as a sentence, some might choose to use the +, - & = signs.

Model the ways your child did not use, e.g. Double 4 is 8 or 4 add 4 makes 8 or 4+ 4 = 8  or

. . . .          .   . . .

    4      add      4       makes  8

Repeat activity using different objects.

Activity;

2 dice game: roll 2 dice and identify if you gave rolled a double. Encourage your child to explain how s/he know it is a double (the two numbers are the same) and how s/he knows it is not a double (the two numbers are not the same.)

When a double is rolled ask your child how they can find out how many “double 3” is “altogether”? Encourage him/her to use language such as “I need to add them together” or “I need to add them to find the total.”

You can play the game with your family.

Activity:

Using dominoes- you can use actual dominoes or you can make your own using paper/card.

If you make your own, you can make doubles up to 5, then up to 10.

The rules for playing and the recording of their findings are similar to the “2 dice game” -see above.

Initially play with a maximum of 10 dominoes and make most of them doubles.

Domino sheet- click on the yellow star with the “Maths sheets” label. If you are unable to print it out, copy the sheet by hand on a piece of paper.

Activity:

Ladybird doubles- with your support, help your child to draw a large ladybird shape with no spots and a line down the middle of the body. Then cut out up to 20 spots- can be any colour.

Place 2 spots on one side of the ladybird’s body and ask your child how many there are. Then ask to “Double 2” and ask them what they are going to do. Your child will add 2 spots onto the other side of the body and add the spots together to find the total, by counting on from 2 (first 2 spots).

Repeat for numbers up to 5, then, if your child is ready, to 10.

Print out the doubling cards - *Click on the yellow star with the “Maths sheets” label to find a copy of them. If you are unable to print them out, then copy by hand onto a piece of paper.

Support your child in reading them and then finding the answer using the spots. Encorage your child to tell you what they have done afterwards.

Halving

Activity:

Explain that half of a shape/object means that it is cut/ divided into 2 equal parts and each half is the same size. 2 halves make a whole.

Halving with playdough or flour and water dough or another soft material- ask your child to roll a snake and then to cut/divide it in half (2 equal parts, both parts being the same size). Questions: How are you going to divide it in half? How do you know that was half? If they make a mistake, discuss the meaning of half and let them have another go. Give him/her support, as and when needed.

Your child can make shapes of their own choice and then ask him/her to divide it in half.

Activity:

Halving shapes- use paper/ card

Ask your child to draw a circle/rectangle/square/triangle. Support them, if they need it. Make sure the shape is a reasonable size. Explain that you want your child to divide the shape in half. Discuss how s/he is going to do it. Suggest folding if your child needs a prompt. Before folding, discuss how to do it so it will be in half. If your child makes a mistake, discuss what a half means and let him/her have as many tries as s/he need to be successful. If you have scissors, let your child cut along the folded line.

Discuss how 2 halves need to be the same size, equal parts and how 2 halves make a whole.

Activity:

Halving food items- this could be halving a cake/pizza/apple/orange. Discuss how to cut the item into half - 2 equal parts, both parts are the same size. Support your child to do this.

Questions: What does half mean? How are you going to divide it into half? How do you know that is cut/ divided into half?

Activity:

Halving amounts/numbers: use a selection of items found around your home (e.g. counters, pebbles, cars, pasta shapes etc.) Model the halving of 2 items. Say half means that you will both have the same amount/number of items. Say “Half of 2 is 1.” Model how to halve 4 items following the same process (Half of 4 is 2) With your child repeat the process for numbers up to 10 and, if your child is ready, go up to 20 items.

Then ask your child to repeat the activity with objects up to 10, then to 20. Encourage him/her to say what they have done afterwards, e.g. “Half of 6 is 3.” Question: How do you know half of 6 is 3? “Because they are the same amount/number.”

Print out the half cards - *Click on the yellow star with the “Maths sheets” label to find a copy of them. If you are unable to print them out, then copy by hand onto a piece of paper.

Support your child in reading them and then finding the answer using their chosen objects.

Repeat the activity at other times using different objects.

Activity:

Halving board – *Click on the yellow star with the “Maths sheets” label to find a copy of the board. If you are unable to print it out, then draw one on a piece of paper.

Print out the half cards - *Click on the yellow star with the “Maths sheets” label to find a copy of them. If you are unable to print them out, then copy by hand onto a piece of paper.

Support your child in reading them and then finding the answer using their chosen objects.

Read a halving card or say “Half of 2” and then place the number of items into the largest rectangle shape on the left-hand side of the board. Then ask your child to halve the objects, placing an equal number/amount in the two smaller rectangle shapes on the right-hand side of the board. Encourage your child to say, “half of 2 is 1.”

Repeat for numbers/amounts up to 10, and, if your child is ready, up to 20.

Doubling and Halving

Point out the relationship between doubling and halving:

Double 1 is 2 and half of 2 is 1.    1 + 1 = 2

Double 2 is 4 and half of 4 is 2.     2 + 2 = 4

Double 3 is 6 and half of 6 is 3.     3 + 3 = 6

Double 4 is 8 and half of 8 is 4.     4 + 4 = 8

Double 5 is 10 and half of 10 is 5.   5 + 5 = 10

etc.