EDMA 163 Louise Penny Abbey Dodds Warm up

EDMA 163 Louise Penny & Abbey Dodds

Warm up How many different shapes can you create joining all 4 of the squares provided? Record each shape. Do all of these shapes have the same area? Do all of these shapes have the same perimeter?

I get the following: 10 units 8 units 10 units Look familiar? Tetris gets in name from a geometric shape composed of four squares known as tetrominoes

Perimeter and Area Children often get confused between perimeter and area. Why do you think this is? Perimeter is the total length of a 2 D shapes sides. Area is the amount of enclosed space within a 2 D shape. The use of language and illustrations of fences (perimeter) and fields (area) help avoid the confusion. Introducing volume and surface area of 3 D shapes creates more confusion!

75 metres 110 + 75 + 110 + 75 = 370 m

110 metres 75 metres 110 x 75 = 8250 m 2

Question 26. 2 Using just rectangular fields drawn on the grid lines on a squared paper, what are the dimensions of the field that gives the minimum length of fencing for an area of 48 squared units?

6 units by 8 units

Perimeter and Circumference What is a circle ? A shape consisting of all the points at a fixed distance from a given point. A line from the centre to any point on the circle is called the radius(r). A line from one point through the centre to the opposite point on the circle is called the diameter(d). (Haylock 2010) Circumference (C) is a special type of perimeter. It is specific to the perimeter of a circle, the circumference of a circle. The formula to calculate perimeter is C=2πr when the radius is know or C= πd when the diameter is known What is pi (π) ? ……

Fun Fact ! Task If I can have some volunteers to trace around something circular, a tin, a glue stick, a cd etc Measure the diameterisand That the circumference always about three times the diameter. roughly the circumference. This wasthe even known by ancient Divide circumference by the civilizations diameter…. What do we find? (Haylock 2010) What is pi? The ratio of the circumference to the diameter of a circle, 3. 14. pi is rounded but goes on forever, an example of an irrational number. 22/7 is a convenient approximation, but is nots its (pi) exact value (CIMT 2010) These circles all have something in common

26. 4: ? ? Can you think of a question that involves circumference ? Use words like diameter, radius, wrap around, walk around, rotation etc Here are some prompts ?

The idea of creating you own question Often students are able to obtain correct answers to a problem without really understanding what they are doing. (Spangler 1992) This process has children show their understanding of the specific wording and concepts. Pupils often confuse radius and diameter or forget to change the formula to when switching between the two. (CIMT 2010)

26. 4: How much ribbon will I need to go once round a circular cake with a diameter of 25 cm C= πd C= π x 25 C= 3. 1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 x 25 C= 3. 14 x 25 C= 78. 5 cm 78. 5 / 25 = 3. 14

Haylock, D. (2010). Mathematics explained for primary teachers (4 th ed. ). London: Sage Publications. Spangler, D. A. (1992). Assessing students' beliefs about mathematics. Arithmetic Teacher, 40, 148 -148. The Centre for Innovation in Mathematics Teaching (CIMT). (2010). Unit 16 Circles and Cylinders - teaching notes. MEP: Demonstration Project (pp. 1 -2). Plymouth: Gatsby Charitable Foundation.