Answer key: Multiplying Fractions with Cross Cancelling
Companion answer key for the printable worksheet "Multiplying Fractions with Cross Cancelling" — Common Core CCSS.MATH.4.NF.A.1, Challenge difficulty. Use it to spot-check during the lesson or grade afterward.
Sample answers
| # | Question type | Sample answer |
|---|---|---|
| 1 | Simplify 4/5 × 2/3 | 8/15 |
| 2 | Simplify 2/5 × 2/3 | 4/15 |
| 3 | Simplify 5/2 × 2/3 | 10/6 |
| 4 | Simplify 4/5 × 2/3 | 8/15 |
| 5 | Simplify 5/3 × 2/3 | 10/9 |
| 6 | Simplify 2/6 × 2/3 | 4/18 |
| 7 | Simplify 3/7 × 2/3 | 6/21 |
| 8 | Simplify 3/3 × 2/3 | 6/9 |
How to grade this worksheet
This answer key is intentionally short — eight items or fewer — so you can spot-check during the lesson rather than waiting until the end. For Math worksheets at the challenge level, we recommend the following grading flow.
- Pencil-only spot check. Walk by every five minutes and circle (lightly) any item that looks off. Do not announce the score.
- Self-grade. When the student finishes, hand them this answer key and let them grade their own work in pen. Self-grading produces about 30% better retention than parent-grading at this age.
- Two-question debrief. Pick the two items they missed and ask: "Walk me through what you tried." Their explanation usually reveals whether it was a careless error or a genuine concept gap.
- Log the score. Note the score, the date, and the standard code (
CCSS.MATH.4.NF.A.1) in your portfolio. Three data points across a month is enough to know if the standard is mastered.
If the student misses more than half of the items, do not reteach the same way. Switch modalities — manipulatives, a drawn diagram, a verbal walk-through — and revisit a fresh worksheet on the same standard the next morning.