Not every half is a mirror

What this lesson shows

Fixes a mistake

Cut corner to corner, a long rectangle makes two equal halves. Folded, they do not match.

The worked example

The lesson works this one step by step: a long rectangle. Then your kid tries one like it on paper.

The steps

1. Equal halves
2. Fold to check
3. A mirror line must match

Helping at home

Cut a paper rectangle corner to corner: two equal halves. Now fold one on that line: the halves do not match. A line of symmetry is a fold where they match.

If your kid gets stuck

Do the halves match when folded?

More in this unit

• Naming flat shapes
• Turned, still a square
• Count sides, not looks
• Sorting shapes
• A square is a rectangle too
• More sides, not more lines
• Perimeter: walk the edge
• Count each unit once
• Perimeter by adding sides
• Opposite sides match
• Perimeter of a pentagon
• Rows and columns of squares
• Faces, edges, and corners