A Part of a Part

Mathematics 5 · Term 1 · Week 7
Name: Section: Date:
Teacher: one page per learner, printed A4. Sections A, B and C count toward Written Works; see assessment.md §1. The two shadings are distinguished by hatch direction, so the sheet still works photocopied in grey. The answer key at the foot of this page is screen-only and will not appear on the printout.

A Shade the grid — across for the first fraction, down for the second

first fraction (shade whole columns) second fraction (shade whole rows) = the product
1. ¾ × ⅔
shaded twice of =
2. ⅗ × ½
shaded twice of =

B Multiply — give the product, then the simplest form

ProblemProductSimplest form
½ × ⅓
⅔ × ¾
⅗ × ½
⅞ × ⅔
¾ × ⅘

C Word problems — underline the word that tells you to multiply

  1. ⅔ of a ₱900 allowance is saved. ¼ of the savings goes on load. How much goes on load?
  2. A ribbon is ¾ m long. ⅔ of it is used. How much is used?

D Which is smaller?

  1. ⅘  or  ⅘ × ⅔
  2. ⅗ × 1  or  ⅗
  3. ½ × ½  or  ½ × ⅓
  4. ⅔ × ¾  or  ⅔ × ⅘

E True or false?

  1. Multiplying always makes it bigger.
  2. ½ × ⅓ is the same as ⅓ × ½.
  3. To multiply fractions, add the denominators.
  4. Two proper fractions give a product smaller than both.

The challenge

? × ? = ¼
  1. Find two different pairs of fractions, both smaller than 1, whose product is exactly ¼. and
  2. In one sentence, explain why ⅘ × ⅓ is smaller than ⅓.
Answer key — screen only, not printed.
A · 1. 6 of 12 = 6/12 = ½ · 2. 3 of 10 = 3/10  |  B · 1/6 → ⅙ · 6/12 → ½ · 3/10 → 3/10 · 14/24 → 7/12 · 12/20 → ⅗
C · 1. ⅔ × 900 = 600, then ¼ × 600 = ₱150 · 2. ⅔ × ¾ = ½ m. The word to underline is of in both  |  D · ⅘ × ⅔ · neither — they are equal · ½ × ⅓ · ⅔ × ¾  |  E · false · true · false · true
· 1. any two of ½×½, ¾×⅓, ⅔×⅜, ⅖×⅝, ⅚×3/10, ⅞×2/7 · 2. any wording showing that ⅘ is less than one whole, so taking ⅘ of something leaves less than you started with. Item ★2 is the diagnostic — a learner can complete everything above it by rule and still believe multiplication makes numbers bigger. Read the sentences first.
Watch D2. "Neither" is the answer; ⅗ × 1 = ⅗. Learners who pick one of them have applied "multiplying makes it smaller" without noticing the multiplier is exactly 1.