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Grade 6 › U04 Fractions › F4
NUMBER · GRADE 6 · ALBERTAOUTCOME AB-MAT6-N6 prep

F4 · Related Denominators: One Common Name for Two Fractions

Learning goal

“I can rewrite two fractions so both use the same denominator — first by finding the relating factor when one denominator is a multiple of the other, and with the product of the denominators when they are not related.”

Common denominator — the same denominator used by two fractions, so both count parts of the same size.
Related denominators — denominators where one is a multiple of the other, like 3 and 6.
Relating factor — the number you multiply the smaller denominator by to reach the larger one.
Multiple — the result of multiplying a number by a whole number: multiples of 3 are 3, 6, 9, 12, …
Worked example

Rewrite 2/3 and 5/6 with a common denominator. Step 1: Are the denominators related? 6 is a multiple of 3 — yes. Step 2: The relating factor is 6 ÷ 3 = 2. Step 3: Scale 2/3 by 2: 2/3 = 4/6. The other fraction already uses sixths: 5/6 stays 5/6. Result: 4/6 and 5/6. Nothing was added — both fractions now count parts of the same size. Model: a bar in thirds with 2 shaded, redrawn in sixths with 4 shaded, beside the sixths bar with 5 shaded, and a 0–2 number line in sixths showing both points, 4/6 and 5/6.

Check yourself — explain it

Why did only one fraction need a new name?

Paired problem — example still visible

Rewrite 3/4 and 7/8 with a common denominator. → 6/8 and 7/8 (relating factor 2)

Faded completion — last step is yours

“Rewrite 5/6 and 11/12: 12 is a multiple of 6, the relating factor is 2, so 5/6 = ___/12 and 11/12 stays.” → 10/12

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

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