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Peabody TeachFor teachers and grown-ups

Fraction bars

Stacked bars for the whole and its halves to twelfths: shade a fraction, line the bars up, see which are equal, and put the shaded ones in order.

11/21/31/41/61/81/12

How to use it

  1. Tap a piece to shade a bar up to it, and tap the same piece again to clear it. The fraction appears at the end of the bar.
  2. Turn on the Guide line to see a dashed vertical line from the end of the last shaded bar down through the others, so you can see which fractions are bigger, smaller or equal.
  3. Type a fraction such as 2/3 under Find equal fractions and press Show them to see every equal fraction up to twelfths shaded together.

Ideas for class

  • Shade 1/2 in the halves and then look down the bars: 2/4, 3/6, 4/8, 5/10 and 6/12 all end at the same line. Ask what students notice.
  • Shade 1/3 and 1/4 and ask which is bigger. Many students think 1/4 is bigger because 4 is bigger than 3.
  • Shade 3/4 and 2/3, then ask the class to order them. The tool writes the order with the right symbol.
  • Ask students to predict, before you tap, whether 5/8 is more or less than 1/2. Tap, and check against the guide line.
  • Find the equal fractions for 2/3, then for 3/4, and ask why there are only a few. The bars only go up to twelfths.
  • Hide most bars (tap the fractions under Which bars) so students compare just two at a time.
  • Turn on Show decimals to connect 1/8 to 0.125 and 3/4 to 0.75.

Related

Questions

Why do the bars all have the same length?

Fractions are always parts of the same whole. When every bar is the same length, a piece of the 1/4 bar and a piece of the 1/3 bar can be compared by eye, which is the whole point of the model.

Which fractions can I show?

Halves, thirds, fourths, fifths, sixths, sevenths, eighths, ninths, tenths, elevenths and twelfths, with the whole. You can show any mix of bars.

How does it know two fractions are equal?

It cross multiplies (3/4 and 6/8 are equal because 3 × 8 = 4 × 6), so there is no rounding. Equal shaded bars get a coloured outline.

Why does 1/5 have no equal fraction in the twelfths?

A fraction can only be matched exactly by a bar whose pieces are a multiple of its own. 1/5 matches tenths (2/10), but 5 does not divide 12, so there is no twelfths bar with a piece of exactly that size. This is itself a useful lesson in why common denominators are needed.

Can students use it on their own?

Yes. Every piece is a button that works with touch, mouse and keyboard (Tab to move, Enter to shade).

Does it keep anything about my students?

No. Which bars you show is remembered in this browser; the shading clears when you leave.

Nothing you do here is sent to us. Names, lists and settings stay in this browser. No sign-in, no ads.

Using fraction bars in class

Fraction bars are the standard tool for showing that a fraction is a size, not just a pair of numbers. Use them to build the idea of equivalence before you teach any rule for it: students who have seen 2/4 end exactly where 1/2 ends do not need to be told that they are equal.

  1. Name the whole, then split it into equal parts and name the parts.
  2. Shade a fraction and read it aloud in two ways (“three fourths”, “three one-fourths”).
  3. Compare fractions with the same denominator (3/8 and 5/8), then with the same numerator (3/4 and 3/8), then neither.
  4. Find equal fractions and ask for the pattern in the numbers (multiply or divide both by the same number).

Misconceptions to expect

  • The bigger the denominator, the bigger the fraction. The bars show the opposite for equal numerators.
  • A fraction needs equal parts. If students draw unequal parts on paper, bring the bars back.
  • Treating the numerator and denominator as two separate whole numbers when comparing (3/4 and 5/8: “5 is more than 3”).