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)

Standard written method for adding decimals

Here we have a very straightforward page of addition questions with decimals. All the numbers use 2 decimal places, so it is very similar to adding money. I have also kept to adding just two numbers so this page is ideal for children who are getting to grips with the standard method of addition.

The only real cause for problems is the decimal point and it is vital that this is written in the answer in line with the other decimal points. The first 9 questions have already been laid out in the correct way but the last three need to rewritten.

Later children will need to add numbers where the number of digits after the decimal point varies eg. 26.4 + 1.78 and it will help enormously if the are confident with how to set them out.

The speed of answering this type of question depends on how well number bonds (eg 5 + 6) have been learned ‘off by heart’.

Divide 3-digit numbers by 6

This is a short division page which concentrates just on dividing 3-digit numbers by 6. Short division, as its name suggests is a shortened version of the long division method where subtractions and remainders are done mentally.

The key to answering these is to have a set speech for the process.

For example: 6)457

‘How many sixes in 45?’

‘7 times 6 is 42.’

‘6 goes into 45, 7 times with 3 left over.’

Write the 7 in the answer above the 5.

Write the remainder three beside the 7 units, making 37.

‘How many sixes in 37?’

‘6 times 6 is 36.’

‘6 goes into 37, 6 times with 1 left over.’

Write the 6 in the answer in the units and write rem 1 next to it.

Division: 3-digit numbers by 6

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

More subtraction using the standard method

I have had several requests for another page of subtracting 2-digits from 3-digits, a worksheet that was published about a month ago. So here it is!

The benefit of the worksheet is that the questions keep to fairly small numbers but increase in difficulty and can show clearly whether children have fully grasped the standard method or whether they need more practice.

The last three questions aer especially tricky and if children are getting these correct it would suggest that they have really understood the concepts.

If these are set as homework make it very clear that all working out needs to be shown (e.g. hundreds crossed out and made one smaller and adjusting 10 tens etc). Of course I see no reason why children should not use a calculator to see if they are correct and if incorrect to try and work out where they have gone wrong.

Standard subtraction of 2-digits from 3-digits (2)

I have had a number of requests for more pages that let children practise the written method of addition, but without making the questions too hard. It is the method which is important to become familiar with. All the rest will depend on how well children know number bonds and can apply them.

The method is to add the units first, put the units in the answer, and ‘carry’ the ten into the tens column. Then add the tens and continue in the same way into the hundreds. So, for a question such as 278 + 546 the steps are:

8 + 6 = 14
Put the 4 in the units below the question.
Then place the one ten below the answer in the tens column.

7 (tens) + 4 (tens) + 1 (ten) = 12 (tens)
Place the 2 (tens) in the tens column and the 1(hundred) in the hundreds column below the answer.

2 (hundreds) + 5 (hundreds) + 1 (hundred) = 8 (hundreds)
Place the 9 (hundreds) in the hundreds column.

Note: there may not always be tens or hundreds to carry.

Standard addition of two 3-digit numbers

Here is a great worksheet for those who are interested in the summer football taking place in July and August. There are 6 stadiums which will host matches:

Hampden Park

St James’ Park

Old Trafford

Wembley

This worksheet looks at the approximate capacity of each ground and asks some tricky questions. Set out over two pages, the answers require addition and subtraction of large numbers as well as long multiplication, including 5-digits multiplied by 2-digits. For this reason it is best suited for the upper primary end. The calculations have been laid out using the standard written method which should help.

Whilst this doesn’t quite fit any category I have added it to the Year 6 Calculations, under Addition.

Subtracting using the standard method

Children need plenty of practice at using the standard written method of subtraction if the are going to become competent with it and calculate without making errors. This is a nice little page as it concentrates on subtracting 2-digit numbers from 3-digit numbers.

More than this the questions are graded in difficulty, according to the rows, so it also makes for an excellent assessment sheet to see just how well they are doing.

The first row is very straightforward, with no adjustments necessary.

The second row questions all require adjustment from tens to units and the third row requires adjustment from the hundreds to the tens.

The last row is the real tester as it needs adjustment from hundreds to tens to units. Watch out for the common erro, such as saying that 0 – 6 is 6.

This page is part of the collection of subtraction worksheets found in the Four Rules category.

Standard subtraction of 2-digits from 3-digits

Written Addition worksheets: 2-digits to 3-digits

Addition of a 2-digit number to a 3-digit number is usually done on paper, using the following standard method:

The method is to add the units first, put the units in the answer, and ‘carry’ the ten into the tens column. Then add the tens and continue in the same way into the hundreds if necessary. So, looking at the addition 278 +37

8 + 7 = 15

Put the 5 in the units below the question.

Then place the one ten below the answer in the tens column.

7 (tens) + 3 (tens) + 1 (ten) = 11 (tens)

Place the 1 (ten) in the tens column and the 1(hundred) in the hundreds

2 (hundreds)  + 1 (hundred) = 3 (hundreds)

Place the 3 (hundreds) in the hundreds column.

Note: there may not always be tens or hundreds to carry.

This type of question is good for children who are not confident with the standard written method of addition.

Standard addition of 2-digits to 3-digits

Resource of the Week: addtion, subtraction, multiplication and division

Most of our calculating worksheets are found in the respective year groups under ‘Calculations’, but I have provided a considerable number of extra pages in the ‘Four Rules’ section of the site which is often overlooked by our browsers.

This section covers both mental and written methods of addition, subtraction, multiplication and division and is steadily increasing over the weeks. With over 100 worksheets already, it covers skills from Year 1 right up to Year 6; from adding a single digit up to long division and there are some very clear descriptions about how to tackle these tasks.

Siome of the most tricky concepts, including the standard methods of multiplication and division can be practiced at length and there are clear set by step guides on how to do them.

Why not go to our Four Rules category