Reflecting on counters
This is a level 3 geometry activity from the Figure It Out series. It is focused on describing the results of reflection. A PDF of the student activity is included.
About this resource
Figure It Out is a series of 80 books published between 1999 and 2009 to support teaching and learning in New Zealand classrooms.
This resource provides the teachers’ notes and answers for one activity from the Figure It Out series. A printable PDF of the student activity can be downloaded from the materials that come with this resource.
Specific learning outcomes:
- Describe the results of reflection.
Reflecting on counters
Achievement objectives
GM3-6: Describe the transformations (reflection, rotation, translation, or enlargement) that have mapped one object onto another.
Required materials
- Figure It Out, Level 3, Geometry, "Reflecting on counters", page 22
- a set of pattern blocks
See Materials that come with this resource to download:
- Reflecting on counters activity (.pdf)
Activity
In this activity, students are developing the concept of symmetrical reflection using mirrors. If you place a mirror across half a shape, the full shape is reflected in the mirror.
This activity allows students to experiment with this concept in a fun problem-solving way.
These answers assume that you have the reflective side of the mirror facing you. The mirror must be one without a frame.
1.
a. Position the mirror halfway over 1 counter as shown below:
b. To see 3 counters, position the mirror as shown below:
c. To see 12 counters, position the mirror as shown below:
2.
All numbers up to 18 are possible if your grid allows you enough room to position the mirror across rows as shown above. Some of the more difficult numbers include:
3.
14, for example,
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