Study Guide — K.CC.A.1
Count to 100 by ones and by tens
This guide helps parents support counting at home. Everyday objects work well — no special materials needed.
What this standard means
- Count aloud from 1 to 100 by ones (1, 2, 3 …)
- Count aloud from 1 to 100 by tens (10, 20, 30 … 100)
- Understand that each number name refers to one more object when counting by ones
- Understand that counting by tens skips nine numbers between each decade
_See printable PDF for diagram._
How to use the 20 practice sets
| Sets | When to use | | --- | --- | | 1–5 | First week — count together, write numerals, identify patterns | | 6–10 | Core practice — sequences, decades, hundred chart | | 11–15 | Mixed review — start-at-N, explain rules | | 16–20 | Stretch — word problems, mastery tasks |
Pacing: 10–15 minutes per session. Praise effort and talking through answers.
How to practice (10–15 minutes)
1. Count aloud — steps, snacks, or toys. Ask: What comes next? 2. Count by tens — use fingers (two hands = 10) or stacks of ten blocks. 3. Fill in the blank — say 48, 49, ___ and let your child supply the next number. 4. Use the hundred chart — point to 10, 20, 30 and trace the pattern. 5. Write numerals — say a number word; child writes the numeral. 6. Explain the rule — by ones we add 1; by tens we add 10.
_See printable PDF for diagram._
Common mistakes
- Skipping numbers — normal at first. Slow down and count together.
- Teens confusion — 13–19 sound similar. Extra practice with 11–19 helps.
- Mixing ones and tens — clarify: by ones we say every number; by tens we jump 10.
Review and practice tests
1. Start Review 1/10 when sets 1–3 feel comfortable. 2. Move up one level when your child completes a review with little help. 3. Use Practice Test 4/10–6/10 for mid-standard check-ins. 4. Practice Test 10/10 is the mastery bar for K.CC.A.1.
- [ ] Counts to 100 by ones without major skips
- [ ] Counts to 100 by tens
- [ ] Can explain the difference between counting by ones and by tens
Materials for this standard
- Practice Problems — 20 printable sets
- Review — 10 difficulty levels (1/10 easiest → 10/10 stretch)
- Practice Test — 10 difficulty levels for progress checks
- Answer key — step-by-step solutions