Study Guide — 1.G.A.3
Partition circles and rectangles into two and four equal shares, desc…
Compose and decompose shapes to make new figures.
What this standard means
- Partition circles and rectangles into two and four equal shares, describe the shares using the words halves, fourths, and quarters, and use the phrases half of, fourth of, and quarter of. Describe the whole as two of, or four of the shares. Understand for these examples that decomposing into more equal shares creates smaller shares.
- Apply partition circles and rectangles into two and four equal shares, desc… with models and explanation
- Composes a target shape from parts
_See printable PDF for diagram._
How to use the 20 practice sets
| Sets | When to use | | --- | --- | | 1–5 | Intro — explore together, short written items | | 6–10 | Core skills — diagrams and written practice | | 11–15 | Mixed review — explain thinking | | 16–20 | Stretch — word problems and mastery tasks |
Pacing: 10–15 minutes per session.
How to practice
1. Make pictures from pattern blocks 2. Trace the parts of a composed shape 3. Fill an outline without gaps
_See printable PDF for diagram._
Common mistakes
- Gaps or overlaps when composing
- Cannot name the parts used
Review and practice tests
1. Start Review 1/10 when sets 1–3 feel comfortable. 2. Move up one review level with little help. 3. Use Practice Test 4/10–6/10 for mid-standard checks. 4. Practice Test 10/10 is the mastery bar for 1.G.A.3.
- [ ] Composes a target shape from parts
- [ ] Fills an outline without gaps
- [ ] Lists shapes used
Materials for this standard
- Practice Problems — 20 printable sets
- Review — 10 difficulty levels
- Practice Test — 10 difficulty levels
- Answer key — for parents and tutors