The term quadrilateral is often  misunderstood and confused with the term rectangle. A quadrilateral is any flat shape which has four straight sides. The angles do not have to be right angles. Rectangles and squares are special cases of quadrilateral.

Look out for quadrilaterals all around you in the real world.

Properties of quadrilaterals

Here is another worksheet for subtraction; this time subtracting 9 from 2-digit numbers.

The usual method to do this in your head is to take 10 and then add 1.

So 56 - 9 is done in two steps:

56 - 10 = 46

46 + 1 = 47

56 - 9 = 47

Subtract 9 from a 2-digit number

Counting on is a very powerful tool when using mental methods of calculating. This worksheet concentrates on counting on a teen number to a number in the hundreds and can be seen as an addition problem (143 + 16).

The usual method of doing this requires the ability to partition (ie know that 16 is 10 + 6) and is in two parts:

1. Count on ten from 143 making 153.

2. Count on 6 from 153 to make 159.

There should not be a need to do this type of question on paper.

Free maths worksheet: counting on (teens)

Continuing with our series of simple addition of single digits, here are two maths worksheets on adding 7. The ultimate aim is for children to know, off by heart, the answer to any addition of two single digits. This means that they don’t have to think about it, there is no counting on in their heads, they know it and can answer as quickly as if they were asked what their name is.

adding 7 to a single digit (1)

adding 7 to a single digit (2)

Find a larger version of this list in the link below.

Remember that new vocabulary should not be introduced in isolation, but in suitable contexts.

(Taken from Mathematical Vocabulary Book DfEE)
Maths vocabulary: multiplication and division

Counting and matching birds p1

Here is a maths worksheets concentrating on mental methods of subtracting a single digit from a teen. Much work needs to be done with subtracting from 10 before moving on to this.

There are really two types of question with these which demand different mental approaches.

The first type:  eg  17 - 6 where it is easy to subtract the 6 from the 7 leaving 11. The tens are not affected.

The second type: eg 16 - 8 where the 8 is larger than the 6 is harder.

One method is add on from 8 to 10 (2 which has to be held ‘in your head’) and then count on from 10 to 16 which is easy (6) and add the two together to get 8. It is surprising how often we add on to do a subtraction sum!

A different approach is to know your doubles: knowing double 8 is 16 means the answer has to be 8.

subtract from teen p1

If you are looking for a great book to help with early counting then Kipper’s Toybox is a must.
Kipper is a cheeky little puppy who is concerned that somebody or something is nibbling a hole in his toybox and that his toys might not be safe. But, the trouble is, that every time he counts them he gets a different number. To make it easier to count  he lines them up.
Then, one night, one of his toys appears to have come to life!
Colourful illustrations and a great story line makes this a fabulous book for all 3+ children.
It could also be used as the basis of a great counting activity at home. Use a box with 5 toys, count them as you put them in. Take one away, count them again and see if your child can spot which one is missing.

I know that a lot of the readers of this blog are teachers, so, if you are a teacher in the UK you might have heard about the Memory 4 Teachers project. The project has been developed, in association with LEAs and Teacher Unions, to support teachers and educators by funding the provision of 750,000 USB memory sticks across the UK – yes, that includes Scotland and Wales!

The sticks have a capacity of 2 GB but are not just empty memory. They will include some great free educational resources and access to some of the best educational sites; from what I have heard the content is going to be really worthwhile. One interesting point is that the memory sticks come with a lifetime guarantee which means that teachers will be able to use the sticks forever.
I believe that the launch of Memory 4 Teachers is due to coincide with the Bett Exhibition in early January.
It is easy for a teacher to register for his/her memory sticks. Just click the link below and complete the online form.
Teacher sign up for memory 4 teachers

Written methods of subtraction often cause problems for children and it is important to state that a good mental knowledge of numbers is essential if written methods are going to be grasped successfully.

In the UK the standard method of subtraction is often known as decomposition. It should be used when numbers are too large or too awkward to subtract mentally. Remember: mental methods should be the first resort!

The first page of the link shows how the decomposition method works, and is probably the one you learnt at school, although there are other, equally valid methods of subtraction.

Standard written subtraction 1