1.10 Grouping  (Page 3/4)

Remember, if you prefer not to do solution directly after the completion, you are free to alter the sequence of the work sheets to suit yourself.

(i) Various triangles: the isosceles; equilateral and rectangular and any other types of triangle.

(ii) Various rectangles and squares.

(iii) Protractors and rulers, enough for everyone in the group.

First establish what the learners already know about the sides and angles of triangles, rectangles and squares.

Measuring angles :

Explain what a right angle is (angle equal to 90°) if they do not know it. Show the learners the protractor and how to measure an angle with it. Make sure that they know exactly how to measure angles.

Let them measure the angles of the various forms on the mat. They must say what they have discovered about the angles of the triangles, rectangles and squares.

All the angles of the rectangles and the squares are right angles . Give them the opportunity to discover other right angles in the classroom.

Have they discovered that a triangle never has more than one right angle? A triangle with a right angle is called a rectangular triangle .

Measuring sides:

Give the learners rulers to measure the sides. Make very sure that all the learners know how to measure using a ruler.

They must discover their own:

There are triangles of which the 3 sides are of the same length. That is an equilateral triangle.

There are triangles of which 2 sides are the same length. That is an isosceles triangle.

There are triangles of which the sides are all different.

The 4 sides of a square are of equal length.

The 2 opposite sides of a rectangle are the same length.

This work will probably not all be done in one mat session, and the time needed will vary depending on the group involved. It is advisable to complete measuring angles in one session and measuring sides in another.

If the learners have already mastered halving of unequal numbers, it is only necessary to explain how to write ½ That means 1 of the 2 parts into which it has been divided:

This is about halving 3,5,7 or 9 groups of ten. There is always 1 ten that must be solved. Encourage the learners to regroup before they halve. They must first do it concretely on the mat.

Every time the numbers 6 to 9 are doubled, a ten is completed.

The learners must indicate it on the work sheet by drawing a circle around the ten.

If there is no calculator available, the educator or one of the learners can write the answers on the blackboard after completing the work sheet. However, the learners who are able to do the calculations on their own, must be allowed to do it.

Encourage the learners to persevere until they find the right “path”. They may require an extra sheet of paper on which to write the numbers while trying to find the correct ones.7

Leaner section

Content

Aactivity: grouping [lo 1.4, lo 1.7, lo 1.8, lo 1.9, lo 1.10, lo 3.1, lo 3.3]

Bonny and Tommy know how easy it is to work with numbers once they have been grouped into tens. Sometimes it is necessary to regroup some of the tens if one has to subtract and there are not enough units to take away.