Minds On

Notice and wonder

A line has been drawn to split different items.

Examine the following chart with all the items.

There is a table with two columns. The first column is called Group 1 and the second column is called Group 2. Group 1 shows an acorn, a red barn, a 4-leaf clover, a button, a bunny’s head, and one pair of scissors. There is a dotted splitting each item into two equal parts. In Group 2, there is a curved arrow, a beaver, a set of three balloons, a coffee mug, and a boot. There is a dotted line splitting each item into two unequal parts.

Brainstorm

Brainstorm

Consider the following questions. If possible, share your thinking with a partner.

  • What do you notice about how the items have been split?
  • Why are the items in two different groups?
  • Can you think of a rule for how the items have been grouped?

Action

Matching halves

A button divided into matching halves by a dotted line. A coffee mug divided in half by a dotted line. The halves of the mug do not match.

When an object is split in half it can either have matching halves or not matching halves.

Matching halves:

  • are the same size
  • are the same shape

Not matching halves:

  • are different sizes
  • are different shapes

Let’s re-examine the items from the Minds On section.

Group 1

Group 2

There is a picture of an acorn with a dotted line running through the middle dividing the acorn into two equal parts.

There is a picture of a barn with a dotted line running through the middle dividing the barn into two equal parts.

There is a picture of a clover with a dotted line running through the middle dividing the clover leaf into two equal parts.

There is a picture of a button with a dotted line running through the middle dividing the button into two equal parts.

There is a picture of a bunny’s head with a dotted line running through the middle dividing the bunny’s head into two equal parts.

There is a picture of scissors with a dotted line running through the middle, dividing the scissors into two equal parts.

There is a picture of an arrow with a dotted line running through the middle dividing the arrow into two unequal parts.

There is a picture of a beaver with a dotted line running through the middle dividing the beaver into two unequal parts.

There is a picture of a set of 3 balloons with a dotted line running through the middle dividing the balloons into two unequal parts.

There is a picture of a mug and a dotted line running through the middle dividing the mug into two unequal parts.

There is a picture of a boot with a dotted line running through the middle dividing the boot into two unequal parts.

Group 1:

  • has matching halves
  • both sides are the same size
  • both sides are the same shape

If we were to fold on the dotted line, the two sides will match exactly.

Group 2:

  • does not have matching halves
  • both sides are different sizes
  • both sides are different shapes

If we fold on the dotted line, the two sides will not match exactly.

Matching or not matching

Let’s play a game!

Examine the following items and decide if they have matching halves or not matching halves.

Select the correct answer, then press “Check Answer” to see how you did.

Practice

Let’s sort some objects!

Examine the following objects.

There is a leaning palm tree, an obtuse triangle, a car, a square, a butterfly, an L shape, a circle, and a kite. Each item is labelled.

Decide which objects have:

  • matching halves
  • not matching halves

Record your thinking using a chart or another method of your choice. You may use pictures, drawings, words, or another method of your choice to represent the objects.

Press ‘Answer’ to access a chart with the objects sorted.

Student Success

Think

What are some other examples of objects that have matching halves?

Consolidation

Construct matching halves

Task 1: Shapes with matching halves

Examine the following geoboards. One half of each shape has already been made.

A geoboard with 5 rows of 5 pegs. A band stretches around some pegs to make a 5-sided shape. The shape looks like half of a heart.
A 5 by 5 geoboard with a band stretching around some pegs to make a 7-sided shape. The shape looks like a rectangle with a triangle cut out.
  • Can you describe or create the matching half?
  • How will you know if the new half is matching with the other half? How could you check?

You may also access the geoboards using the following printable document.

Geoboard halves

Press the Activity button to access the Geoboard halves.

Activity (Open PDF in a new tab)

Task 2: Everyday objects with matching halves

Find an object in your classroom, home or community that has matching halves.

  • Describe the object or create a drawing of it, if possible.
  • Explain how you know it has matching halves.

Reflection

How do you feel about what you have learned in this activity? Which of the next four sentences best matches how you are feeling about your learning? Press the button that is beside this sentence.

I feel…

Now, record your ideas about your feelings using a voice recorder, speech-to-text, or writing tool.