3.6 Number block

Mathematics

Bonny and tommy visit the zoo

Educator section

Memorandum

• Number Concept to 1 000 (These are the minimum requirements for Grade 3.)
• Operations:
• Addition – two and three digit numbers with and without regrouping of the tens and/or hundreds.
• Subtraction – two and three digit numbers with and without regrouping of the tens and/or hundreds.
• Multiplication – two and three digit numbers with a one digit number, with or without regrouping of the tens.
• Division – two digit numbers with a one digit number with regrouping of the tens but without a remainder, e.g. 75 ÷ 5 =

(In the following module remainders with regrouping of the tens are practised again).

In Module 6 the number concept is extended to 1000. Addition and subtraction is done with two- and three-digit numbers, with and without regrouping of tens and hundreds. Multiplication is done with two- and three-digit numbers with and without regrouping of tens. Division is done with two-digit numbers and regrouping of tens only, without a remainder in Module 6,

e.g. 75 ÷ 5 = £ (In the following module, the remainder will be included in regrouping.)

Learners need to know what the actual paper money looks like: R10-, R20-, R50-, R100- and R200-notes.

They must understand the values and be able to do simple calculations.

Explain what drawing to scale signifies. They will have to be able to grasp this concept very well before they will be able to calculate the lengths of the elephants’ trunks. Provide similar examples to ensure that they are able to do the exercise.

The learners need to develop a concrete image of the numerical value of 1000.

999 + 1 completes a ten that is taken to the tens to complete 10 tens which make a hundred. The hundred is taken to the hundreds to complete 10 hundreds. These make a group of a thousand which has to be taken to the thousands.

1000: the 1 represents 1 group of a thousand and the 3 noughts are the placeholders for the hundreds, tens and units.

Once the learners have completed the number block, it must be used for many counting exercises in tens and hundreds, counting forwards and backwards.

If learners are still struggling to master doubling and halving, they should be encouraged to use the "cloud" to assist the thinking process.

First work orally with similar examples using letter values, before allowing the learners to do the worksheet.

Multiplication with three-digit numbers, with regrouping of the tens, must first be practised orally and in the concrete.

Let the learners count in 9’s before asking them to write it.

Help them to realise that it is easier to start by adding 10 and subtracting 1 than it is to add 9. The opposite is done when 9 is subtracted: take away 10 and add 1. Let them use counters.

If 10c and 1c pieces are used to explain the idea of regrouping tens during division, the learners will be helped to grasp that the tens have to be broken up and regrouped with the ones before it can be shared out. (Play money could be used.)

The learners may need much practice before they will have enough skill to complete the worksheet.