## Maths worksheet: subtract from 20 mentally

There are a number of different ways in which subtraction problems can be phrased including terms such as ‘Take from’ and ‘How many more’. This maths worksheet looks at some of them, whilst concentrating on subtracting from 20 using mental methods.

The usual method of mentally subtracting is to ‘add on’. For example 20 – 7.

Add 3 to 7 to make 10 and then add a further 10 to make 20. Answer 3 + 10 which is 13.

Or, the ten could be added first to make 17 and then count on to 20.

Either way is equally good.

Subtract from 20 (pg 1)

We usually think of an addition number sentence with the two numbers to add already given and just the answer to work out. This page looks at it from a different angle; giving the answer and asking for two numbers which will complete the sum correctly. This is a good exercise to show children that there are often several ways to complete a problem.

Complete the addition sums (pg 1)

## LEGO Universe: great for technology and maths education

Lego Universe
We all recognise the little blocks and most of us will have used them at some time. They have always had great potential for Technology and Maths teaching but now LEGO is moving into new areas, both great online gaming  and serious technological innovation.

Lego is currently developing its first ever massively multiplayer online game called LEGO Universe, aimed at players from the age of 8 upwards.

universe.lego.com, at the moment is just a pre-launch site. Soon you will be able to customise your own tiny in-game characters and guide them through virtual worlds. You want more bricks to build? Then you will have to complete challenges, defeat enemies and unlock secrets.

If you are looking for the sort of cross curricula educational experience recommended by the Cambridge Primary Review last week, then this is just the right kind of thing.
Find out much more at

LEGO

## Y4 free maths worksheet: place value

Knowing what each digit in a number represents can be a real challenge for children. Many do not understand that the digit 4 in 3400 has a different value to the digit 4 in 340. That is why understanding place value is so important once children begin to use larger numbers.

Here is a worksheet which should demonstrate whether place value has been understood. It asks what number needs to go into each box to make the number sentence correct. It shows that, for example:

2345 is made up of 2000 + 300 + 40 + 5

Place value (pg 1)