Fraction Classroom · 2.0.0 · Student pages

Use a benchmark, then justify

Sort fractions around one half and one, then recognize when a shared benchmark does not settle a comparison.

Anonymous group code: __________   Date: __________

Quick diagnosis

Try all three. Explain with words, a sketch, or objects.

d1. Is 5/12 below or above 1/2? Name one half in twelfths.

d2. Compare 3/8 and 5/6 using one half.

d3. Both 2/3 and 3/4 are above 1/2. Does that fact alone tell which is larger?

Worked examples

Study the example that matches the difficulty. Keep the other for a second session.

w1. Compare 2/5 and 7/12 using one half.

  1. Two groups of 2 fifths make 4/5, less than a whole, so 2/5 is below half.
  2. Half of twelve equal parts is six parts; 7/12 exceeds 6/12.
  3. One fraction is below 1/2 and the other above it.
  4. Place 2/5 to the left of 7/12.

Worked example: 2/5 < 7/12.

w2. Compare 5/6 and 7/8 by thinking about what is missing from 1.

  1. Both fractions are one equal part short of a whole.
  2. Write the missing amounts: 1/6 and 1/8.
  3. A sixth of the same whole is larger than an eighth.
  4. Removing the larger gap leaves the smaller fraction.

Worked example: 5/6 < 7/8 because 1/6 is a larger missing amount than 1/8.

Practice

For a short session, choose three tasks. Use the others for a second try or follow-up.

p1. Sort 2/5, 4/8, and 5/6 as below, equal to, or above 1/2.

p2. Compare 3/10 and 3/5 using one half.

p3. Which is closer to 1: 4/5 or 5/6? Explain with missing parts.

p4. A student says 1/3 = 2/5 because both are below 1/2. Explain the mistake and compare them.

p5. Choose a benchmark of 0, 1/2, or 1 that separates 7/8 and 9/8. Write a comparison.

p6. Give one fraction below 1/2 and one above 1/2, both with denominator 5. Explain your choices.

Transfer check

Try one independently. Save the other for a later check.

t1. A bottle is 5/12 full and another same-sized bottle is 3/5 full. Which has more liquid? Use a benchmark and state the needed whole-size condition.

t2. Compare 5/6 and 3/4. Explain why “both are above half” is incomplete, then finish using a suitable method.