1. You have just completed a learning unit on ordinary fractions. Let us do some revision.

What fraction in each of the following figures is coloured in?

1.1

Figure 1

1.2

Figure 2

1.3

Figure 3

2. Write the answers above as decimal fractions.

Refresh your memory!

We read 0,3 as nought comma three and we call it a decimal fraction.

The comma is called the decimal sign and it separates the whole numbers from the fractions.

Do you still remember?

1 10 1 10 size 12{ { {1} over {"10"} } } {}

Figure 4

3. Look at the number line and fill in the missing numbers.

Figure 5

4. Work together with a friend. Count aloud and complete the following:

4.1 0,2 ; 0,4 ; 0,6 ; .............. ; .............. ; .............. ; .............. ; .............. ;

4.2 4,7 ; 4,5 ; 4,3 ; .............. ; .............. ; .............. ; .............. ; .............. ;

4.3 0,5 ; 1,5 ; .............. ; .............. ; .............. ; .............. ; .............. ;

4.4 3,6 ; 3,2 ; .............. ; .............. ; .............. ; .............. ; .............. ;

4.5 9,2 ; 9,1 ; .............. ; .............. ; .............. ; .............. ; .............. ;

Do you still remember?

If I want to add 0,3 to the previous number repeatedly I can programme my calculator in this way: Number+ 0,3 + = = =

By now you know that we can use the pocket calculator very effectively to find or check answers. Now that you have seen how to programme your pocket calculator or to add on, try to complete the following activity without making any mistakes. Programme your pocket calculator and write the first 10 answers to the following:

1.1 Start at 3,7 and add 0,6 each time:

1.2 Start at 9,3 and subtract 0,4 each time:

In this activity we would like to see whether you can determine which ordinary fractions (mixed numbers) fit in with which decimal fractions. It is important for you to be able to see that 0,2kg is actually exactly the same as 210210 size 12{ { {2} over {"10"} } } {} kg !

1. Link the ordinary fractions to their decimal fraction partners. Connect column A to the correct answer in column B.

Challenge!

2.Work with a friend. Write the following fractions as decimal fractions:

2.1 4545 size 12{ { {4} over {5} } } {} 2.2 220220 size 12{ { {2} over {"20"} } } {}

2.3 3535 size 12{ { {3} over {5} } } {} 2.4 720720 size 12{ { {7} over {"20"} } } {}

2.5 18301830 size 12{ { {"18"} over {"30"} } } {} 2.6 48604860 size 12{ { {"48"} over {"60"} } } {}

3. Explain what must be done to get the above answers.

4. How can you check your answers with a calculator?

5. Now use a calculator to check your answers in no. 2.

1. You now have the opportunity of improving your mental arithmetic skills and applying your newly acquired knowledge. Complete the following mental arithmetic test as quickly and as accurately as possible:

Look carefully at the following:

100 c = R1,00

1c = 11001100 size 12{ { {1} over {"100"} } } {} of a rand

1c = R 11001100 size 12{ { {1} over {"100"} } } {} R0,01

1. By now you have probably discovered that when we work with rand and cents we are actually working with hundredths! Look carefully at the example above and than write the following in rand:

1.1 4 c .........................

1.2 38 c .........................

1.3 2 c .........................

1.4 303 c .........................

1.5 460 c .........................

Did you know?

11001100 size 12{ { { size 8{1} } over { size 8{"100"} } } } {} is written like this as a decimal fraction: 0,01. We read it as nought comma nought one. If we have less than 1010010100 size 12{ { { size 8{"10"} } over { size 8{"100"} } } } {} we must write 0 (nought) as a place-holder after the decimal comma, in the place of the tenths.

Let us look again at our number system:

1 100 1 100 size 12{ { {1} over {"100"} } } {}

Figure 6

2. What fraction of the following is NOT coloured in? Write it also as a decimal fraction.

2.1

Figure 7

2.2

Figure 8

2.3

Figure 9

2.4

Figure 10

2.5

Figure 11

2.6

Figure 12