Page 37 - Mathematics Coursebook

3.3 Ordering decimals

3 Greg uses the symbols < and > to show
that one number is smaller than or larger 4.07 is smaller than 4.15, so 4.07 < 4.15
than another.
Write the correct sign, < or >, between 2.167 is bigger than 2.163, so 2.167 > 2.163
each pair of numbers.

a 6.03 6.24 b 9.35 9.41 c 0.49 0.51 d 18.05 18.02
The symbol < means ‘is
e 9.2 9.01 f 2.19 2.205 g 0.072 0.06 h 29.882 29.88
smaller than’.
The symbol > means ‘is
bigger than’.

4 Ulrika uses a different method
to order decimals. Her method
is shown on the right. Question
Use Ulrika’s method to write Write the decimal numbers 4.23, 4.6 and 4.179
the decimal numbers in each in order of size, starting with the smallest.
set in order of size, starting Solution
with the smallest. 4.179 has the most decimal places, so give all
a 2.7, 2.15, 2.009 the other numbers three decimal places by
b 3.45, 3.342, 3.2 adding zeros at the end: 4.230, 4.600, 4.179
c 17.05, 17.1, 17.125, 17.42 Now compare 230, 600 and 179: 179 is
smallest, then 230 then 600
Numbers in order of size are: 4.179, 4.23, 4.6

5 The table shows six of the fastest times run by women in the 100 m sprint.

Name Country Date Time (seconds)
Kerron Stewart Jamaica 2009 10.75
Marion Jones USA 1998 10.65

Merlene Ottey Jamaica 1996 10.74
Carmelita Jeter USA 2009 10.64
Shelley-Ann Fraser Jamaica 2009 10.73

Florence Griffith-Joyner USA 1988 10.49

Who is the fourth fastest woman runner? Explain how you worked out your answer.
6 Brad puts these decimal number cards in order of size, starting with the smallest.
He has spilt tea on the middle card.
3.07 3. 3.083

Write down three possible numbers that could be on the middle card.

36 3 Place value, ordering and rounding