April, 2009 | Maths Blog

Standard method of short multiplication pg 2

Here is another maths worksheet to practice the standard method known as short multiplication. All these sums have already been set out in the correct way but it is important to remember to keep the units in the units, tens in the tens column etc. This will become even more important when decimals are introduced later.

Always work in the same order, starting by multiplying the units, carrying any tens on into the tens column and then multiplying the tens. Perhaps the key to success with these is knowing the times tables up to 10 times 10. If each multiplication has to be worked out the whole task becomes laborious.

Standard method of short multiplication pg 2

News: upcoming maths resources

I hope you all had a great Easter holiday, but now we are moving towards one of the most important terms of many children’s lives, with SAT tests, new school placements, trips out etc. Coming up in the near future are some great maths resources on multiplying by whole tens and short multiplication. We also have a look at some fractions material for younger children who are just getting to grips with halves and quarters. There will also be an excellent page on place value with decimals for Year 5 children. All coming soon.

Year 4 maths worksheet: Placing negative numbers

This worksheet takes another look at negative numbers and where they are positioned on a number line. This is a good exercise in helping children to count back through zero and then from a negative number forwards, again through zero. Each number line has a different starting and finishing number so care needs to be taken.Try to use the term ‘negative’ rather than ‘minus’ when referring to the numbers.

Place negative numbers on a number line (pg 1)

Year 4 Maths worksheet: negative numbers

Negative numbers become an important part of maths in Year 4. Usually the best way to teach it is through practical work such as the use of thermometers when the temperature drops below zero. Whilst temperature is read using the term ‘minus’ it is a good idea to read negative numbers as ‘negative 3’ or ‘negative 5’.

There are 2 ideas at work here. Firstly, understanding the idea of numbers smaller than zero can be tricky. Children might ask how you can have a number smaller than nothing. An overdraft is always a good starting point to explain this! Also the idea that a larger digit can portray a smaller number eg -6 is smaller than -1.

This maths worksheet uses number lines that go from left to right, from a negative number through zero to positive numbers.

Order negative numbers pg 1

Maths worksheet: Standard short multiplication 1

This is the standard written method known as ‘short multiplication’. It leads on from the earlier worksheets on ‘Moving towards a standard method’.

Before starting this type of sum a good knowledge of times tables is needed.

The stages are as follows:

Step 1: write the sum out correctly

The question may be put in a different layout eg 38 x 7 =

Make sure it is laid out with the units under each other as shown on the example.

Step 2: multiply the units

Multiply 8 by 7 which 56 or 5 tens and 6 units.

Put the 6 in the answer in the units and place the 5 (tens) in the tens column, under the answer line. Continue reading “Maths worksheet: Standard short multiplication 1”

News: upcoming maths worksheets

I hope you have all had a good Easter. During the next week we have some great maths worksheets on the standard method of short multiplication, tables, plus paper and pencil methods for division. Also look out for a great negative numbers worksheet, suitable for year 4. We have over 500 pages of free maths resources on the site now – don’t forget to tell your friends!

Times Table practice: 2, 3, 5 and 10 times tables

This is the second in a continuing series of times table practice for the 2, 3, 5 and 10 times tables.

Any child who knows their tables off by heart is at a huge advantage over those who don’t know them. Many maths problems and techniques, such as long multiplication and division, rely on knowing tables, so it is really worth the effort to learn them. Watch how the grid is filled in as it gives good clues as to what has been learned (which takes no time at all to answer) and what has been ‘worked out’ (which might take a while). Say the table out loud many times – there are songs and recordings that will help.

2,3,5 and 10 times table p2

Year 6 Maths worksheet: Ordering fractions

$ordering-fractions$ The big question: how do you put fractions in order of size? It is easy to compare fractions if the bottom number (the denominator) is the same for each fraction. 3/12 is smaller than 5/12 etc. But if the denominators are different it becomes more tricky.

There are several ways to do this (eg treat each fraction as a division sum and use a calculator to work out the division answers and then order them) but the established method is to change each fraction so that they all have the same denominator.

Warning! If children are going to be successful with this there are several things that they already need to be confident with, including knowing tables and being able to recognise multiples of a number. They also need to know that multiplying the numerator (top) and denominator (bottom) of a fraction by the same number will not change the fractions size – equivalent fractions again! Without this knowledge they will be doomed and confused!!

Let’s take 3/4 and 2/3 as a simple example. To be able to directly compare them the denominators of both fractions need to be the same. Both fractions can be shown in twelfths. (If you don’t understand why I have chosen twelfths then have a look at some of the equivalent fraction pages on the site.)

3/4 can be changed by multiplying 4 by 3 and then 3 by 3 to give 9/12.

2/3 can be changed by multiplying 3 by 4 and 2 by 4 to give 8/12

From this it can be sen that 2/3 or 8/12 is smaller than 3/4 or 9/12.

There is a more detailed explanation on ordering fractions on the maths worksheet pages.

Ordering fractions p1

Year 4 maths worksheet: multiplying by 10 and 100

Understanding what happens when you multiply a whole number by 10 is crucial to understanding maths at primary school and indeed with later maths. Children should have carried out lots of practical work with base 10 apparatus in school to show that:

when you multiply a whole number by 10 the digits move one place to the left.

Now this may give the appearance of ‘adding a nought’ as a zero is placed in the units. I know of many teachers and publishers who still use this expression, but it is extremely dangerous, especially when it comes to multiplying decimals by 10. (0.8 is not 0.80).

Multiplying by 100 is the same as multiplying by 10 and then multiplying by 10 again (10 x 10 = 100) so each digit will move two places to the left and zeros will need to be placed in the units and tens.

When you multiply a whole number by 100 the digits move two places to the left.

Multiplying by 10 and 100 (pg 1)

Maths worksheet: Standard written multiplication 3-digits by 1 digit

This worksheet uses the standard or efficient method recommended by the Primary Framework for Maths to multiply a 3-digit number by a single digit. There are other methods equally good, but it is important that children keep to one method that they become confident with. It presumes a good knowledge of tables before starting.

For example: 436 x 7.

First, do an estimate of the answer.
436 x 7 is approximately 400 x 7 which is 2800. The answer will be over 2800.
Then set the sum out in a vertical layout:
436
x 7

Start with the units.
6 x 7 is 42. Put the 2 in the units and carry the 4 tens into the tens column, under the answer line.
Then multiply the tens.
3 (tens) x 7 is 21(tens). Add the 4 (tens). to make 25(tens).
Place the 5 in the tens column and carry the 2 (hundreds) into the hundreds column.

Finally the hundreds.
4 (hundreds) x 7 is 28 (hundreds). Add the 2 (hundreds) to make 30 (hundreds).
Place the zero in the hundreds column and the 3 in the thousands column.
The answer is 3052.
A clearer layout of this is available on the worksheet explanation.

Further written multiplication worksheets can be found in the Year 5 and Year 6 Calculations sections.

Standard written multiplication: 3-digits by 1-digit