Answer key: Determining Decimal Value with Blocks
Companion answer key for the printable worksheet "Determining Decimal Value with Blocks" — Common Core CCSS.MATH.5.NBT.A.3, Easy difficulty. Use it to spot-check during the lesson or grade afterward.
Sample answers
| # | Question type | Sample answer |
|---|---|---|
| 1 | 7 + 2.3 | 9.3 |
| 2 | 5.6 + 9.2 | 14.8 |
| 3 | 1 + 1 | 2.0 |
| 4 | 3.1 + 4 | 7.1 |
| 5 | 6.3 + 8.7 | 15.0 |
| 6 | 9.4 + 1.1 | 10.5 |
| 7 | 8.6 + 6.6 | 15.2 |
| 8 | 7.8 + 3.8 | 11.6 |
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 easy 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.5.NBT.A.3) 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.