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  1. In this activity you will again have the opportunity of trying to find different solutions to the same problem with your friends. Divide into groups of three. Discuss the following problem and solutions (methods) and then explain them to a friend who doesn’t understand as well as you do.

Loretta’s practice times for gymnastics are as follows Monday : 2 hours 40 min Wednesday : 1 hour 55 min Thursday : 3 hours 18 minHow much time does she spend practising altogether?

1.1 2 hours 40 min + 1 hour 55 min + 3 hours 18 min

2 h + 1 h + 3 h = 6 h

40 min + 55 min + 18 min = 113 min

= 1 h 53 min

Thus: 6 h + 1 h + 53 min = 7 h 53 min

1.2 I prefer to write the time below each other:

2 h 40 min

1 h 55 min

3 h 18 min

6 h 113 min

= 6 h + 1 h + 53 min (113 min = 1 h 53 min)

= 7 h 53 min

2. Whose method do you like best?

Why?

Activity 10:

To solve problems that include selecting, calculating with and converting standard units

[LO 4.6]

1. In the previous activities you were exposed to a variety of methods. Now use any method and calculate:

1.1 3 weeks 5 days + 7 weeks 6 days + 9 weeks 2 days

1.2 8 days 17 hours + 5 days 21 hours + 4 days 19 hours

1.3 6 hours 45 min + 3 hours 38 min + 2 hours 54 min

1.4 5 min 29 seconds + 9 min 43 seconds + 4 min 42 seconds

1.5 7 years 9 months + 6 years 8 months + 5 years 11 months

Activity 11:

To determine the equivalence and validity of different representations of the same problem through comparison and discussion [LO 2.6.1]

1. Look at the following problem and then discuss the solutions together as a class. Make sure that you understand each method very well.

Sven has been following the programme “Survivors” on TV and noticed that team A took 4 days 18 hours to cover a certain distance. Team B took 7 days 5 hours to complete the same distance. How much longer did team B take?

1.1 I must calculate 7 days 5 hours – 4 days 18 hours.

4 days 18 hours to 5 days = 6 hours

5 days to 7 days 5 hours = 2 days 5 hours

2 days 5 hours + 6 hours = 2 days 11 hours

1.2 7 days 5 hours – 4 days 18 hours

7 days 5 hours = 6 days 29 hours (1 day = 24 hours)

6 days – 4 days = 2 days

29 hours – 18 hours = 11 hours

The answer is thus 2 days 11 hours

1.3 I answer it in this way:

6 5 + 24 = 29 (1 day = 24 hours) 7 days 5 hours

− 4 days 18 hours

2 days 11 hours (29 – 18)

Which method do you understand the best?

Activity 12:

To solve problems that include selecting, calculating with and converting standard units [LO 4.6]

1. Use all the knowledge that you have gained up to now, choose a method you prefer, and calculate the following:

1.1 19 weeks 3 days - 12 weeks 5 days

1.2 17 days 13 hours - 11 days 19 hours

1.3 9 hours 34 minutes - 3 hours 47 minutes

1.4 15 years 7 months - 9 years 10 months

CHALLENGE!

See if you can get the following information from a library (or perhaps the internet!)

1. How did all the months of the year get their names?(You already know about August).

2. Why does February only have 28 days?

3. Why do some months have 31 days and other months have 30 days?

Make a colourful poster showing the above information and share it with the class.

Assessment

LO 4
MeasurementThe learner will be able to use appropriate measuring units, instruments and formulae in a variety of contexts.
We know this when the learner:
4.1 reads, tells and writes analogue, digital and 24-hour time to at least the nearest minute and second;
4.2 solves problems involving calculation and conversion between appropriate time units including decades, centuries and millennia;
4.3 uses time-measuring instruments to appropriate levels of precision including watches and stopwatches;
4.4 describes and illustrates ways of representing time in different cultures throughout history;
4.5 estimates, measures, records, compares and orders two-dimensional shapes and three-dimensional objects using S.I. units with appropriate precision for:
  • mass using grams (g) en kilograms (kg);
  • capacity using millimetres (mm), centimetres (cm), metres (m) en kilometres (km);
  • length using. millimetres (mm), centimetres (cm), metres (m) en kilometres (km);
4.6 solves problems involving selecting, calculating with and converting between appropriate S.I. units listed above, integrating appropriate contexts for Technology and Natural Sciences;
4.7 uses appropriate measuring instruments (with understanding of their limitations) to appropriate levels of precision including:
  • bathroom scales, kitchen scales and balances to measure mass;
  • measuring jugs to measure capacity;
  • rulers, metre sticks, tape measures and trundle wheels to measure length.

Memorandum

ACTIVITY 1

1.

1.1: 12

1.2: April; June; September; November

1.3: January; March; May; July; August; October; December

1.4: 365

1.5: 366

1.6: 29

1.7: 5

1.8: 60

1.9: 60

1.10: 24

1.11: 52

1.12: 15

1.13: 45

1.14: 31

BRAIN-TEASER!

10

1 000 years

century

ACTIVITY 3

  1. measures time to one hundredth of a second

ACTIVITY 4

1.

1.1:

180

150

45

54

3 600

1.2

120

90

15

190

1 440

1.3

may differ

168

30

6

1.4

56

11

182 1 2 size 12{ { { size 8{1} } over { size 8{2} } } } {}

732

BRAIN-TEASER!

299

ACTIVITY 5

2.1 seven o’clock / 07:00 / 19:00

2.2 20 min. past 3 (p.m.)

2.3 five min. to 7 / 06:55 / 18:55

2.4 10 min. to 9 (a.m.)

2.5 1 4 size 12{ { { size 8{1} } over { size 8{4} } } } {} to 5 (a.m)

2.6 half past 7; 19:30; 07:30

3. 3.1: 06:20

3.2: 18:30

3.3: 15:45

3.4: 00:00 / 24:00

3.5: 02:42

3.6: 20:36

3.7: 17:15

ACTIVITY 8

1. 1.1: 19 h 24 min.

- 06 h 52 min.

12 h 32 min.

1.2: 13 h 40 min.

- 01 h 41 min.

11 h 59 min.

2.

06:40; 07:05; 07:30

07:55; 08:20; 08:45

09:10; 09:35; 10:00

3.

3.1: 08:25

3.2: 16:48

3.3: 21:22

3.4: 04:15

ACTIVITY 10

1.

1.1: 19 w 13 d

= 20 w 6 d

1.2: 19 days 9 hours

1.3: 13 hours 17 min.

1.4: 19 min. 54 sec.

1.5: 20 years 4 months

ACTIVITY 12

1.

1.1: 6 weeks 5 days

1.2: 5 days 18 h

1.3: 5 hours 47 min.

1.4: 5 years 9 months

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Source:  OpenStax, Mathematics grade 5. OpenStax CNX. Sep 23, 2009 Download for free at http://cnx.org/content/col10994/1.3
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