# Four Operations

## Four Operations Revision

**The Four Operations**

The **four operations** include **addition**, **subtraction**, **multiplication**, and **division**.

**Addition**: operation to find the total of two or more numbers.

**Subtraction**: operation to find the difference between two numbers.

**Multiplication**: operation to find the product of two or more numbers.

**Division**: operation to split a number into equal parts.

**Addition**

**Simple addition questions**, like 5+11, can be easily calculated ourselves or by using a calculator and typing in 5+11= giving us 16.

We may come across more complicated questions, such as:

If Sally has \text{£}12, and for her birthday she is **given** \text{£}230 from her mum, \text{£}162 from her dad, and \text{£}51 from her brother, how much money does she now have?

We can similarly work this out by typing the following into our calculator:

12+230+162+51=\text{£}455

**Subtraction**

Similarly to addition, we can use our calculator to work out subtraction questions, for example:

If Sally has \text{£}455, and she **spends** \text{£}80 on shoes, \text{£}118 on jumpers, and \text{£}66 on jewellery, how much money would she have remaining?

We can work this out by typing the following into our calculator:

455-80-118-66=\text{£}191.

**Multiplication**

**Simple multiplication questions**, like 4\times5, can be easily calculated ourselves or by using a calculator and typing in 4\times5=, giving us 20.

We may come across more complicated questions, such as:

Freddie **buys** 6 chocolate bars for 55\text{ p} each, how much does he spend in total?

We can similarly work this out by typing the following into our calculator:

6\times55=330\text{ p}.

**Division**

Similarly to multiplication, we can use our calculator to work out division questions, for example:

Freddie **spends** 605\text{ p} on chocolate bars. Each chocolate bar costs 55\text{ p}, how many chocolate bars does Freddie buy?

We can similarly work this out by typing the following into our calculator:

605\div55=11 chocolate bars.

**Example 1: Simple Operations**

Use your calculator to work out these four operation questions:

a) 16+12+31+40

b) 109-34-12-9

c) 3\times5\times9\times18

d) 100\div4\div5

**[4 marks]**

a) By typing the sum into a calculator:

16+12+31+40=99

b) By typing the sum into a calculator:

109-34-12-9=54

c) By typing the sum into a calculator:

3\times5\times9\times18=2430

d) By typing the sum into a calculator:

100\div4\div5=5

**Example 2: Applied Operations**

Bart is going to a supermarket. He buys a bag of kiwis for \text{£}3, some yoghurts for \text{£}4 and 6 toothbrushes each priced at \text{£}1.

By using multiplication and addition, calculate how much money Bart spent overall at the supermarket.

**[3 marks]**

Firstly, we can work out how much he spent in total on toothbrushes by **multiplying** the price by the number of toothbrushes bought:

Now, we can **add up** everything he bought to find his total:

## Four Operations Example Questions

**Question 1: **Emma collects stamps. On Monday she had 55 stamps. On Tuesday she collected 4 more stamps from her parents’ letters. On Wednesday her friend gave her 11 more stamps. However, on Thursday she fell over on her way to school and lost 28 of her stamps.

How many stamps did she have left after losing some?

**[3 marks]**

Monday: 55

Tuesday: 55+4=59

Wednesday: 59+11=70

Thursday: 70-28=42

Therefore, she had 42 stamps remaining.

**Question 2:** 4 friends are going on holiday together. In total, they spent \text{£}600 on flights, \text{£}1800 on a hotel, and \text{£}300 on baggage.

Calculate how much they each spent on their holiday.

**[3 marks]**

We can firstly use addition to calculate the total cost for all 4 friends:

\text{£}600+\text{£}1800+\text{£}300=\text{£}2700We can then divide this by 4 to calculate how much each person spent.

\text{£}2700\div4=\text{£}675**Question 3: **A teacher has 160 colouring pens to share between her class of 32 students, and she wants each student to get the same amount of colouring pens. She shares them out equally.

However, by the end of the day, each student has lost 2 colouring pens each.

How many colouring pens did each student have by the end of the day?

**[4 marks]**

Firstly, we can share the 160 pens between the 32 students using division:

160\div32=5So, each child has 5 colouring pens.

Then, each child loses 2 pens:

5-2=3Therefore, by the end of the day, each student has 3 colouring pens.