2.2 Halve  (Page 3/4)

Once more discuss the different ways in which to divide squares and rectangles into halves and quarters.

Much concrete and semi-concrete work must be done when the learners have to divide numbers into quarters, especially when the number is not a multiple of 4. Use objects such as fruit and soft sweets that can actually be broken up quite easily, and not hard objects such as marbles, stones or bottle caps.

Explain to the learners that it will depend on the problem whether you can break it up into fractions or not.

Look at this: Daddy has 25 sheep that have to be herded into 4 pens. How many sheep will there be in each pen? (The remaining sheep cannot be cut up.)

Daddy has slaughtered 25 sheep and takes them to 4 butcheries. How many does each butchery get? (It will certainly be possible to divide the remaining sheep into 4.) Discuss more similar examples.

As soon as the learners understand that 4x is 2 times doubled, and 4÷ is two times halved, this can be drilled, because they must know the tables.

This is a wonderful way of familiarising learners with posing problems, but it demands much and regular practice. As soon as they understand it and can do it with confidence, they put forward wonderful ideas.

Begin with a very simple number sentence, e.g. 3 + 4 = □. Initially, let the learners name objects with which they can possibly work, and write these suggestions on the blackboard: trees, flowers, sweets, sheep, dogs, etc.

Everyone must be involved and try to give suggestions. Make the rows compete and then let them pose the problems as a kind of competition.

The vertical addition and subtraction calculations have been graded from simple to difficult so that it will be easy for you to determine a learner’s problem(s). This will enable you to concentrate on the problem areas only and to give appropriate similar exercises to help them.

With the last row of addition calculations, completing the hundred (carrying over the tens) is done incidentally to determine which of the learners understand this already. However, you are free to facilitate this formally now.

It must be a pattern that is repeated every 2 blocks and therefore it must be exactly the same throughout. It can also be offered with Technology, and the learners can then draw their own blocks on a larger sheet of paper.

Explain rounding off to the nearest R to the learners. Let them bring old catalogues and practise rounding off until they understand it.

This worksheet will give you a good idea of which learners are able to follow and carry out instructions.

Any learner who has a good grasp of hundreds, tens and units at this stage, should be capable of completing this worksheet quite easily. Point out to the learners that if they do not get the same answer in the balloon vertically and horizontally, there is a mistake somewhere and they will have to check the answers vertically and horizontally again.

More examples with smaller numbers can also be given.

Leaner section

Content

Activity: halve [lo 1.4, lo 1.7, lo 1.8, lo 1.10, lo 3.1, lo 3.3, lo 4.6]

• Bonny and Tommy want to make a party hat for each child. You will have to help with the design. Complete yours and tell us how you planned and made it.