2.5.1 MATHEMATICS
2.5.2 Bonny and Tommy visit the farm 2.5.3 EDUCATOR SECTION
2.5.4 Memorandum
• Number Concept to 600
• Operations:
• Addition two and three digit numbers with and without regrouping of the ten.
• Subtraction two and three digit numbers with and without regrouping of the ten.
• Multiplication two digit number with a one digit number without regrouping the tens to 99.
• Division two digit numbers divided by a one digit number without a remainder or regrouping the tens to 99.
• The 3× and 3÷tables to the tenth multiple are taught. These conclude the tables to be learnt in Grade 3. Repetition and testing should be done regularly.
• The telling of time is very important. It is recommended that this be done classically as it requires much preparation and is immensely time consuming.
The learners each need a clock to handle and can construct one out of cardboard before the lesson.
In module 4 the number concept is extended to 600. Addition and subtraction calculations include two and three digit numbers. Multiplication and division calculations are done without regrouping of tens, and only up to 99.
In learning 3x and ÷ up to the 10th multiple, the tables that have to be mastered in Grade 3 are completed. Regular repetition and testing are vitally important from this stage on.
It is recommended that the reading of time be done with all the learners at the same time. Each learner must have a cardboard clock to use when the work is being done.
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Such a clock can be made from a paper plate, or the learners can be allowed to design their own clock for Technology. However, it must be ready before the reading of time is started in class. A great deal of practical exercise is necessary before the learners can complete the worksheets.
Number concept is now extended from 400 to 600 and the number blocks of hundreds, tens and units, as well as the ared cards, (attached to Module 2), must still be used to promote the number concept. Give special attention once again to the 100 that must be regrouped when 300 and 500 are halved: 300 = 200 + 100 500 = 400 + 100
Counting in sixes must be done incidentally and can also be repeated on the multiples chart (Module 2). Learners must know: 1 dozen = 12.
Learners must have the opportunity, and be encouraged, to say what they can deduce from the graph, what can change and what will not change, before they have to write about it. Such a discussion will give you a good indication of what the learners understand and which aspects need more attention.
Learning 3x and ÷ must be done on the mat and with the use of concrete apparatus. The worksheets are only there to apply what has already been taught.
Learners must get the opportunity in class, on a daily basis if possible, to take measurements with the ruler, the metre stick and the trundle wheel. The more practice they get, the more accurately they will measure. However, always encourage them to estimate rst.
This is enrichment work and if you nd that it is too advanced, it can be done at a later stage. There may be learners who would like to accept the challenge.
Seeing that 3x and ÷have just been done, it is easy to introduce thirds now. Give the learners loose paper shapes and allow them to fold and measure on their own, so that they can discover how it can be done. Some of the learners will know how to nd sixths without any help. (Only enrichment)
The idea with the recipe is to make the learners understand that certain standard units and containers must be used, otherwise there is no chance of success with a recipe.
Let the learners mention more examples of the use of standard units in practice, e.g. petrol, milk, mixing medicines, prescriptions for administering medication, etc.
It is essential that all the dierent standard measuring containers and scales, as well as sand, water and objects used in measuring volume and mass, should be available in the classroom. Learners should be able to experiment every day with measuring and weighing, using standard units: litres and millilitres and grams and milligrams.
A bathroom scale is required to determine the mass of the learners.
Dierent methods are used for the multiplication and division calculations, but should you prefer another method and you nd that the learners understand it better, it is their right to use the preferred method.
It is essential that many similar examples of the relevant number sentences be done orally before the learners are expected to complete this worksheet.
The regrouping of a hundred when adding or subtracting is now formally taught. Sucient concrete work must be done beforehand. More advanced work where a ten and a hundred are regrouped simultane-ously, should not be done at the same time. It will depend on the abilities of the group whether it should be done immediately hereafter or at a much later stage.
Whether the learners will be allowed to make use of carried numbers, remains the decision of the educator.
e.g.Learners will need a blank sheet of paper in order to calculate the shortest route. Some learners may nd it dicult and may want to give up, but with a little help they should be able to do it.
A discussion on what they will see as they approach the farmstead by road is necessary before the learners will be able to draw it.
2.5.5 LEANER SECTION 2.5.6 Content
2.5.6.1 ACTIVITY: To read time [LO 4.1, LO 4.2]
• Bonny and Tommy each got a watch for their birthday. Take a paper plate or cut a circle from cardboard and design your own clock (watch) from which you can tell the time.
Remember::
1 day = 24 hours 1 hour = 60 minutes 1 minute = 60 seconds
Figure 2.25
•
Figure 2.26
What is the time?
• Draw the long and the short hands on the clocks
Figure 2.27
• Bonny and Tommy went to play at a friend's house at two o' clock, and they returned home at ve o' clock. How many hours had they been away from home?
They had been away for _______________________________________ hours.
• An hour can be divided into 2 half-hours 1 hour = 60 minutes
half-hour = 30 minutes
Figure 2.28
• What is the time?
Figure 2.29
• Draw the long and the short hands on the clocks:
Figure 2.30
• Bonny and Tommy each does 8 sums in half an hour. How many sums will they do altogether in 1 hour?
They will do _________________________________________________________
• Mother drives 50 km in half an hour. How far will she drive in 2½ hours?
She will drive _________________________________________________________
• How many half-hours are there in 4 hours? 4 hours = __________ half-hours
• An hour can be divided into 4 quarters. Then you have 4 quarters of an hour.
1 hour = 60 minutes half-hour = 30 minutes quarter-hour = 15 minute
Figure 2.31
• What is the time
Figure 2.32
• Draw the long and the short hands on these clocks::
Figure 2.33
• Complete the table:
quarter-hours 1 2 3 4 5 6 7 8
minutes 15 30
Table 2.24
Figure 2.34
• What is the time?
Figure 2.35
• Draw the long and the short hands on the clocks::
Figure 2.36
• Mother went to the shop at 3 o'clock and returned home by 20 past 4. For how long had she been away?
She had been away for __________________________________________________
• It takes Bonny 5 minutes to read 3 pages of her book. How many pages can she read in 1 hour?
She can read _________________________________________________________
• Father entered the bank at 5 past 2 and came out 45 minutes later. At what time did he come out?
It was ______________________________________________________________
2.5.7 Assessment
Learning Outcome 4:The learner will be able to use appropriate measuring units, instruments and formulae in a variety of contexts.
Assessment Standard 4.1: We know this when the learner reads and writes analogue and digital clock time in terms of hours, half-hours, quarters of an hour and minutes;
Assessment Standard 4.2: We know this when the learner solves problems involving calculations with and conversions.