Page 9 - TM Brochure 2018

of a circle of radius r cm. cher into 24 equal parts.
Cut out each part of the circle.
ow. For the final part, cut it into half as shown d.
Pair and Share Work in pairs.
Give real-life examples of changes in quantities. Explain how the percentage change is calculated.
Show and Say
Work in groups.
The table shows the temperatures recorded in Singapore from 12 midnight to 8 p.m.
radius
r cm
nce × radius
dius × radius dius
a circle = r 2
Note: Prices based on the Department of Statistics average retail prices of selected consumer items.
Play and Learn
Source: Department of Statistics Singapore
40 35 30 25 20 15 10 5 0
Temperatures in Singapore
12 midnight 4 a.m. 8 a.m. 12 noon 4 p.m. 8 p.m.
Time
le adth
Example
1st roll
The figure looks like a rectangle. Its length is about half the circumference of the circle.
Play in groups.
Take turns to roll a 10-sided dice twice. Find the change (increase or decrease) in the numbers shown on the dice. Express the change as a percentage of the first number rolled.
Midnight 4 a.m.
8 a.m. 12 noon 4 p.m.
8 p.m.
17/5/17
6:22 PM
C04_6A TB TMath.indd 95
95
15/5/17
11:14 AM
69
15/5/17 11:41 AM
What is the area of this circle?
A newspaper reported changes in some food prices as shown below.
Time of Day
12 midnight 4 a.m.
8 a.m. 12 noon
4 p.m.
8 p.m.
Temperature (°C)
29 25 30 35 32 30
Some of the biggest price increases
January 2014 May 2014
% increase
Some of the biggest price decreases
January 2014 May 2014
% decrease
Papaya (per kg)
$1.95 $2.18 11.79 Tomatoes (per kg)
$2.88 $1.72 40.28
Spinach (bayam) (per kg)
$2.87 $3.13 9.06 Medium prawns (per kg)
$22.93 $18.04 21.33
Pear (each)
$0.93 $1.01 8.6 White pomfret (per kg)
$29.51 $23.82 19.28
Thai rice 100% fragrant (5 kg)
$12.54 $13.06
4.15
Vitamin enriched bread (400 g)
$1.76 $1.72 2.27
(a)
(b)
C09_TM 6B TB.indd 69
A line graph and a pie chart are used to present the data in the above table. Discuss the suitability of the graphs used to present the data.
Share the reasons with the class.
2nd roll
8 – 6 = 2
Percentage decrease = 28 × 100% = 25%
Discuss examples of data that may be presented in pie charts. Can they be represented in other forms of graphs?
Temperature (°C)