Category: Maths news

Subtraction of decimals

Here we have another page which looks at the written method of subtracting decimals. The key here is to lay the question out in the traditional method, with the smaller number below the larger number and with the decimal points in line.

Sometimes these can be quite tricky; for example with a subtraction such as 8.5 – 6.26 it is important to write down a zero making the 8.5 into 8.50.

Also watch out for children who subtract the top number from the bottom number in an attempt to avoid the ‘decomposition’ process.

Standard subtraction of decimals (1)

Resource of the Week: probability as a fraction

Probability does cause some confusion with children, partly because it can be expressed in several ways and because it is very hard to find events which are absolutely certain to happen, or not happen.

One way of displaying the probability of an event is as a percentage: for example, there is a 50% chance of landing on a head when tossing a coin.

Another way is as a fraction: there is 1/2 chance, or one in two chance of landing on heads.

A third way is as a decimal fraction, where zero means no chance and 1 is certain: there is 0.5 chance of landing on heads. Probability can be displayed along a number line marked from zero to one.

A the end of the page there is a tricky probability line where the events have to be placed in order of likelihood.

This year 6 maths worksheet is the second published which looks at probability as a fraction and then as a decimal fraction. A calculator would be useful to do the conversion and it is suggested that the answer should be displayed to 2 decimal places. A useful homework sheet.

Giving the probability as a fraction_(pg 2)

Calculating in Year 2

In Year 2 children will be calculating using the addition, subtraction, multiplication and division symbols. Their understanding of addition will develop as they begin to add a 1-digit number to a 2-digit number as well as beginning to answer written addition questions. (This is not the same as using written methods.) Developing efficient mental methods of addition and subtraction are still the most important aspects here, as written methods, apart from jottings, should not yet be used.

Subtraction is much easier once it is realised that it is the inverse (or opposite) of addition. Many subtraction questions can be answered by adding on, but children are expected to know subtraction facts to at least 10 (eg know that 9 – 4 = 5). Knowing these facts is just as important as knowing ‘tables’. They will also be working with 2-digit numbers, especially multiples of 10.

There is a good selection of addition and subtraction worksheets on the site in our Year 2 calculating section as well as a growing number of multiplication and division pages. Multiplication is seen as repeated addition and the 2x, 5x and 10x tables will be learned during the year.

As well as in the Calculating section further worksheets can be found in Knowing Number Facts and our Four Rules section.

Go to Year 2 calculating worksheets

Resource of the Week: Bar charts

Now we are coming on to more familiar territory for most people when we think of graphs: the bar chart or bar graph. Here the vertical bars represent the number of people going out on a boat. Each bar is completely separate from the others.

It is important that children get used to naming the horizontal and vertical axes and that these axes should always be named.

The hardest part of interpreting this bar chart involves the number of people shown on the vertical axis. The numbers go up in twenties, but of course there are intermediate values. The number of people on the 11.00 boat is more difficult to read and only a close approximation between 120 and 140 can be made. As it looks just less than half way to the next interval an estimate of just below 130 would be very accurate.

It is important not to just look at the graph but to also make some suggestions as to why the results are as they are. Why did the 12.00 boat have the least number of people on it, but the 1.00 boat had the most?

The second worksheet has similar problems, but the numbers on the vertical axis go up in tens rather than twenties.

Free Y4 maths worksheet: Bar charts (pg 1)

Free Y4 maths worksheet: Bar charts (pg 2)

Counting and Number in year 2

A great deal is expected of children by the end of Year 2 and we have some great maths worksheets to help them on their way.

By the end of the year children are expected to read and write 2-digit numbers in figures and words, describe and extend number sequences and recognise odd and even numbers.

They should continue to gain confidence with counting in singe steps up to at least 100 and begin to count in twos, fives and tens. Estimating a number of objects and rounding 2-digit numbers to the nearest ten are also introduced in Year 2.

There are a number of pages on counting on and back in ones and tens, finding missing numbers on number squares as well as recognising simple fractions.

Go to our year 2 Counting and Number worksheets

Short multiplication (multiplying by 3)

Today I have published a page of multiplication questions which can be used to reinforce knowledge of the 3 times table as well as practising the short method of multiplication. it is called the short method because it does not involve writing to answer to each part of the question on a new line and then adding the totals, rather it is all done on one line. The main thing to remember is to carry the extra tens into the tens column and remember to add them into the final answer. A page at the start shows how to go about using this method.

The primary Framework for Mathematics is very keen to emphasise that written methods of multiplication should only be used when children have established a sound foundation of mental methods.

This page can be found in the Four Rules, Multiplication category, along with lots more.

Short multiplication for multiplying by 3

Resource of the Week: Weather chart

It’s lovely and sunny here and the Olympics are well under way, so what better than a weather chart to brighten the day even further!

This worksheet shows a weather graph of the average maximum and minimum temperatures for each month of the year for London and shows just why August is a pretty good month to hold a sports competition. It is typical of many found on weather sites on the internet, holiday brochures and newspapers. It is well worth reminding children that a graph should always have a clear title, and the axes labelled.

Some children have problems interpreting the scales on graphs when they don’t go up in single figures so it is important to point out what the temperature scale is. Most suited to year 5.

Weather chart (1)

Resource of the Week: Standard metric measures

With the Olympic Games just beginning now is a great time to brush upon those standard metric units of measurement. No longer do athletes run 100 yards or a mile: in fact the Olympics have always been metric and it is the system that all children are taught in school.  By Year 4 children should be quite familiar with the main metric units of measurement and should know the following:

1 kilometre = 1 000 metres

1 metre = 100 centimetres

1 metre = 1 000 millimetres

1 centimetre = 10 millimetres

1 kilogram = 1 000 grams

1 litre = 1 000 millimetres

It is a good idea to tell children that mille is Latin (and French) for 1 000, not one million!

This page is a good check of understanding this and getting children to use these units of measurement.

Standard metric units

Ordinal numbers maths worksheet

Once children have got a really good knowledge of numbers they can start to look at ordinal numbers. Whilst young children are not expected to know the term ‘ordinal numbers’ they are expected to know and understand terms such as first, second, third etc. This language can be developed during the playing of games whilst discussing who should go first, escond etc.
This is a simple wordsearch using these terms. All the words can be found either going across or down – there are no diagonals. It is good practice to help with reading and writing these words as some of them are quite tricky.

Ordinal numbers wordsearch

Maths worksheet: Archery (2)

Archery is one of the oldest known sports; certainly it was a competitive activity in medieval times – remember Robin Hood! In the 14th century it was compulsory for all men aged between 7 and 60 to practise.

The idea of the sport is to shoot arrows at a target consisting of ten rings, with the Gold in the middle. Usually it takes the form of a knock-out competition with five sets. Each set consists of three arrows per archer.

This worksheet looks at the possible scores that can be achieved if all the three of the arrows land in the red and/or blue rings.

The Red Inner is worth 8 points.

The Red outer is worth 7 points.

The Blue Inner is worth 6 points.

The Blue Outer is worth 5 points.

This is a slightly harder task than the first Archery worksheet. When carrying out this look for children who work in a well organised, methodical way e.g. starting with the highest possible score (8, 8, 8) and working down. probably most suired to year 4/5 and can be found in our Year 5 Using and Applying Maths section.

Archery worksheet (2)