## Standard written addition of 4-digits

Addition of two 4-digit numbers 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 and finally the thousands.

A clearer explanation is available on the first page of the worksheets, together with a page of questions, but briefly:

Looking at 5687 + 2546 the steps are:

7 + 6 = 13

Put the 3 in the units below the question.
Then place the one ten below the answer in the tens column.

8 (tens) + 4 (tens) + 1 (ten) = 13 (tens)
Place the 3 (tens) in the tens column and the 1(hundred) in the hundreds column below the answer.

6 (hundreds) + 5 (hundreds) + 1 (hundred) = 12 (hundreds)
Place the 2 (hundreds) in the hundreds column and the 1(thousand) in the thousands column below the answer.

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

5 (thousands) + 2 (thousands) + 1 (thousand) = 8 (thousands)
Place the 8 (thousands) in the thousands column.

Standard addition of 4-digits (pg 1)

## Mental arithmetic: Know by Heart Pairs that Make 20

This maths worksheet for year 2 children looks at pairs of numbers which make 20. Before doing this children should be confident with, and know by heart, all pairs of numbers which make 10. Once they know these, pairs that make 20 becomes easy; just one of each pair is ten more e.g. 6 and 4: 16 and 4. Being able to work quickly with mental arithmetic is one of the keys to success in school as so much of the maths lesson today is carried out orally and children gain or lose confidence very quickly when answering in front of a whole class.

Know  pairs that make 20 (pg 1)

## Maths Worksheet: Add 9 Mentally

Being successful with mental arithmetic is all about having a ‘feel for numbers’ and being able to manipulate them to suit the way you like to calculate. Knowing a few basic ‘tricks’ helps enormously with this and gives children confidence.

Adding 9 might sound a little dull, but knowing that you can do it in your head by adding ten and subtracting one can make all sorts of other mental additions easy, as we will see later adding 19, 29, 39 etc all follow the same path as do adding 18, 28, 38 etc; these tasks which at first glance might seem tricky end up being easy.

This is suited to year 3 children who are confident with adding single digits and can count up to 100.

## Y2 addition worksheet: find the missing number

Sometimes sums can prove to be more difficult than they first appear. For many children this is the case with the kind of questions on this worksheet which require finding the missing number. Why is this difficult? Because it involves carrying out two processes, when children are used to only having to do one thing to find the answer. Whilst it is an addition number sentence, subtraction is needed to work out the answer.

There are several methods which could be used to find the answer, but the most efficient is probably to:

1. Add the two single digits

2. Subtract that total from the answer.

Another way is to start with the answer and find it on the number line, then hop back the first number, then hop back the second number. Where you land is the answer.

Find the missing number: adding 3 numbers

## Maths worksheet: adding 4-digit numbers (1)

Addition of two 4-digit numbers is usually done on paper, using the standard method described on the worksheet. Once addition of HTU has been mastered it is a fairly straightforward step to adding thousands, eg
5 6 8 7 + 2 5 4 6

The key is to keep the numbers in line (tens under tens etc) and to always start with the units. Most children will not have a problem with this and many really enjoy completing sets of sums. It is a good idea to encourage checking by doing the inverse ie subtracting the second number from the answer to give the first number. This checking could be done on a calculator.