Everyday maths 1 (Wales)
Everyday maths 1 (Wales)

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Everyday maths 1 (Wales)

4.4 Decimal problems

Now try the following activity.

Activity 33: Using decimals

Solve these problems involving decimal numbers without using a calculator.

Described image
Figure 25 Using decimals
  1. You buy a box of corn flakes for £2.65 and a bottle of milk for £1.98.
    • a.What is the total cost of these items?
    • b.You pay for them with a £5 note. How much change should you get?
  2. You go on holiday to Italy. The rate of exchange is £1 = €1.4. How many euros do you get for £8?
  3. You go out for a meal with three friends, and the total cost of the meal is £56.60. You decide to split the bill equally. How much does each of you pay?
  4. Convert 6.25 m to cm. (Remember that 100 cm = 1 m.)

Answer

  1. The answers are as follows:
    • a.Add the cost of the two items:

      The sum £2.65 + £1.98 = £4.93.

      (Keep the decimal points in line.)

      The total cost of the items is £4.63.

    • b.Take away the total cost from £5:

      The sum £5.00 – £4.63 = £0.37.

      You should get 37p change from £5. You may have used a different method to work this out.

  2. Multiply the exchange rate in euros (€1.4) by the amount in pounds (£8):

    The sum 1.4 × 8 = 11.2.

    So £8 = €11.20. You may have used a different method to work this out.

  3. Divide the total cost (£56.60) by the number of people (4):

    The sum 56.60 ÷ 4 = 14.15.

    You would each pay £14.15.

  4. To convert 6.25 m into cm, you need to multiply the amount by 100.

    • 6.25 × 100 = 625

    So the answer is 625 cm.

Summary

In this section you have learned about how:

  • the value of a digit depends on its position in a decimal number
  • to approximate answers to calculations involving decimal numbers
  • to add, subtract, multiply and divide using decimal numbers.

This will help when working with money and measurements.

FSM_1_CYMRU

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371