Susan C. Anthony

Fractions 5: Fractions of shapes other than circles

Note:  Depending on the age and maturity of your students, this lesson can easily be combined with the last lesson.

Materials:

  • Paper squares, triangles, rectangles, L-shapes, etc.
  • Student worksheets.

Note:  Words in green are words the teacher actually says.

Review:

  • So far, we've learned to identify and name fractions, and we've learned about numerators and denominators.
  • Give review practice. Hold up fractional pieces for identification, put them on an overhead, or draw them.
  • What does the denominator stand for? (The number of pieces in a whole, or the number of people you're sharing with.)
  • What does the numerator stand for? (The number of pieces you're talking about.)

Anticipatory Set:

Learning:  Today you will work with fractions of shapes other than circles. What will you do today?

Purpose:  The concept, or idea, of fractions, extends to all things and all shapes. Although we will use mostly fractions of circles because they are easy to identify and manipulate, you need to know that the same concept applies to all shapes.

Transfer: The way to name and identify fractional parts of other shapes is exactly the same as you learned for circles. Count the total number of equal sized pieces in a whole for the denominator. The number of pieces you're talking about is the numerator. What is the numerator?  How do you find the denominator? How do you find the numerator?

Teach:

  • We've been working mostly with circles. Draw a circle on the board.
  • What shape was the candy bar we cut into fractions the first day? (Rectangle) Draw a rectangle.
  • What are some shapes other than circles and rectangles? (triangle, square, parallelogram, L-shape, etc.)
  • Draw a rectangle and divide it, but not in half. If I divide the rectangle like this, have I divided it in half? (No.) Why not? (The pieces aren't equal.) Remember that the pieces must be equal to be named as fractions.
  • Draw a square and draw lines from corner to corner and side to side so it is divided into eights. If I divide a square like this, what have I done? (You've divided it into eighths.)
  • Shade 5/8. What have I shaded? (5/8) How do I write that?

Guided Practice

You will be doing a worksheet today similar to the one we did yesterday. Be sure to read the directions carefully. When you are finished, raise your hand and I'll check your paper. When most people are finished, we'll check the whole thing together.

Circulate during guided practice, giving reinforcement or assistance as needed.

Closure

Correct papers together.

  • Today you learned that the concept, or idea, of fractions applies to all kinds of shapes. What are some shapes it applies to besides circles.
  • Tomorrow you will begin using your own fraction kits to learn a very important fact about fractions.

Go on to read Fractions 6: Parts to Wholes
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