3.4 Tables and checks to arrange and record data

Mathematics

Grade 5

Ordinary and decimal fractions

Module 49

Tables and checks to arrange and record data

Activity 1:

To use tables and checks to arrange and record data [lo 5.3]

1. Use your existing knowledge to complete the following table:

Brain-teaser!

What will the following fractions look like if written as decimal fractions on the calculator?

1. $\frac{3}{\text{100}}$ ______

2. $\frac{9}{\text{100}}$ ______

3. $\frac{\text{40}}{\text{100}}$ ______

4. $\frac{\text{80}}{\text{100}}$ ______

5. $\frac{\text{37}}{\text{100}}$ ______

6. $\frac{\text{59}}{\text{100}}$ ______

How do the answers of 3 and 4 differ from the rest?

Why is this?

Did you know?

Normally we don’t write the noughts at the end of decimal fractions, but in the following cases we do:

a) When we work with money : R8,60 (shows how many cents there are).

b) When we time an athlete with a stop-watch : 7,30 seconds. This is how we give results to the hundredth of a second.

1. When Mom buys material : 1,70 m (so that the saleslady knows exactly how many cm to cut).

Activity 2:

To recognise and represent numbers [lo 1.3.3]

1. It is sometimes difficult to determine exactly where a decimal number fits into the greater whole. A number line is a handy way of helping you to determine this, because it helps you to “see” the sequence of the numbers. Draw arrows and label with the letters given to indicate more or less where the following numbers will be on the number line:

A : 5,82

B : 5,99

C : 6,09

D : 6,24

Activity 3:

To use a series of techniques to do mental arithmetic [lo 1.10.2]

1. Let us play a game!

Work with a friend. Take turns. Close your eyes and press on any number in the diagram on the next page with the back of your pencil. Open your eyes and tell your friend what the number consists of:

e.g. 14,38 = 14 + $\frac{3}{\text{10}}$ + $\frac{8}{\text{100}}$

Colour in every number you get right green. Your friend colours all his / her correct numbers blue. The one who has something wrong misses a turn. The one who has coloured in the most blocks, wins.

Activity 4:

To recognise and classify numbers in order to compare them [lo 1.3.3]

1. By now you know how to write tenths and hundredths as decimal fractions. Look very carefully at the following numbers. Replace the * with<,>or =.

Hint: You should break the numbers up as in the game above if you have any doubts about the correct answer.

1.1 1,7 * 1,07 _____

1.2 0,6 * 0,06 _____

1.3 0,58 * 0,9 _____

1.4 0,34 * 0,4 _____

1.5 2,05 * 2,5 _____

1.6 1,8 * 1,80 _____

Brain-teaser!

What does one quarter ( $\frac{1}{4}$ ) look like as a decimal fraction?

Can you write the following as decimal fractions?

a) $\frac{3}{4}$ : _____

b) $\frac{1}{\text{25}}$ : _____

c) $\frac{3}{\text{20}}$ : _____

d) $\frac{\text{17}}{\text{50}}$ : _____

Activity 5:

To use tables and checks in order to arrange and record data [lo 5.3]

1. Challenge!

Take a measuring tape and measure the height of five of your class mates (to 2 digits after the decimal comma). List your results in a table and number your friends from the shortest to the tallest.

Thousandths

Did you know?

When I write one thousandth $\frac{1}{\text{1000}}$ as a decimal fraction, it will be 0,001.