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Maths

Multiplying and dividing by 10

 

In Year 4 children need to understand what happens to numbers when they are multiplied and divided by 10 and 100.  Today (22.01.20) we learnt about multiplying and dividing by 10 and what happens to the numbers on a place value grid.

 

The following BBC Bitesize clip is very helpful.  It has some following up activities too.

 

How to multiply by 0, 1, 10 and 100

 

 

On Tuesday  (07.01.20) the children enjoyed an active maths lesson where they had to work in small groups to write maths problems.  The document below contains one problem (written by the children) from each group.  Print it off and have a go!

Today, I introduced the children to the concept of 'factors'.  I like this definition of a factor:

 

Numbers we can multiply together to get another number.

 

It can be easier to think of factors in pairs, 'factor pairs'.  For example the factors pairs of 10 are:

 

1 and 10 (1x10=10 or 10x1=10)

2 and 5 (5x2=10 or 10x5=10)

 

For more information and activities on factors click on these links:

 

What are factors? (BBC Bitesize)

Factors (Maths is Fun)

 

We also played a game called 'Factor Mining'.  This is a good game to secure the understanding of factors.  The instructions and game grid can be obtained by clicking on the pdf file below.

Divisibility Rules

 

Is 3417 divisible by 3?  Other ways of saying this could be:

 

Can 3418 be divided by 3?

Does 3 fit exactly into 3417?

 

To check this you can use the following rule: the sum of the digits is divisible by 3

 

Add all the digits together - 3417 - 3+4+1+7=15

Can the answer be divided by 3.  Yes it can - there are exactly 5 threes in 15.  15 divided by 3 = 5

 

For other divisibility rules have a look at this web page.  It's taken from an American site called 'Maths is Fun'.  I've used this website a lot and think it's really good.

 

Divisibility Rules (Maths is Fun)

The document below shows a variety of games you can play with your times table cards.

Today (26.11.19) we learnt how to use a formal written method when subtracting one number from another.  Mr Chandler showed us when the bottom number is smaller than the top number we have to regroup a number to the left of it.  It used to be called 'borrowing'.  The clip below shows how to do this.

 

How to use column subtraction (BBC Bitesize)

 

The document below contains five subtraction sums.  Print them off and have a go.  Mr Chandler would be very happy to mark them if you bring them into school.

Below are instructions for playing two different card games that help with adding two 4-digit numbers: Hidden Addition and Regroupy.  Have fun!laugh

Hidden Addition and Regroupy

Activities to help speed up times table recall

 

Hit the Button

Multiplication Tables Check (Mathsframe)

Over the last couple of days (21-22.10.19) we have been learning a new strategy to subtract mentally.  It's one of many strategies that children can use if they want to.  Below is a document showing how to work through this strategy step by step.  There are also three questions.

Minuend

Today (14.10.19) in maths we learnt a new strategy to help add numbers together: Think 100 and Think 1000.  When adding two numbers you regroup (split) at least one of them so you can easily make 100 or 1000.  You then add on the other numbers.  The document below gives a fuller explanation with examples and questions to try out - have a go.

 

Think 100 and Think 1000

Estimating magnitude

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