Study Guide — 1.NBT.C.5
Given a two-digit number, mentally find 10 more or 10 less than the n…
Understand that digit position determines value — ones, tens, hundreds, and beyond.
What this standard means
- Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
- Apply given a two-digit number, mentally find 10 more or 10 less than the n… with models and explanation
- Identifies value of each digit
_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. Use base-ten blocks or place-value charts 2. Write numbers in expanded form 3. Compare numbers starting with the largest place
_See printable PDF for diagram._
Common mistakes
- Treating digits as separate counts
- Zeros in the middle of numbers
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.NBT.C.5.
- [ ] Identifies value of each digit
- [ ] Writes expanded form
- [ ] Reads and writes numbers in standard form
Materials for this standard
- Practice Problems — 20 printable sets
- Review — 10 difficulty levels
- Practice Test — 10 difficulty levels
- Answer key — for parents and tutors