1.1 Combining operations
Often in daily life you will come across problems that require you to use more than just one of the operations in order to answer the question.
Example: Combining operations
Four friends are planning a holiday. The table below shows the costs:
|Flight (return)||£305 per person|
|Taxes||£60 per person|
|Hotel||£500 per room. 2 people per room|
|Taxi to airport||£45|
The friends will be sharing the total cost equally between them. How much do they each pay?
First we use multiplication to find the cost of items that we need more than one of:
Flights = £305 × 4 = £1220
Taxes = £60 × 4 = £240
Hotel = 2 rooms required for 4 people = £500 × 2 = £1000
Now we use addition to add these totals together along with the taxi fare:
£1220 + £240 + £1000 + £45 = £2505
Finally, we need to use division to find out how much each person pays:
£2505 ÷ 4 =£626.25 each
Activity 2: Combining operations
Your current mobile phone contract costs you £24.50 per month.
You are considering changing to a new provider. This provider charges £19.80 per month along with an additional, one off connection fee of £30.
How much will you save over the year by switching to the new provider?
£24.50 × 12 = £294 (current provider)
£19.80 × 12 = £237.60
£237.60 + £30 = £267.60 (new provider)
£294 − £267.60 = £26.40 saved
The answer to Activity 2 is a convenient, exact amount of money. However, often when you perform calculations, especially those involving division, you do not get an answer that is suitable for the question. This leads you to the next section: rounding.
In this section you have:
- revised the four operations – addition, subtraction, multiplication and division
- practised using these operations including combining them to solve problems.