Counting and Writing to 120
A 40-minute Grade 1 lesson taking the count past 100, where the sequence finally becomes regular and the hardest joins are the ones either side of a hundred.
Counting and Writing to 120 is a free 40-minute Grade 1 maths lesson plan for Common Core standard 1.NBT.A.1 — count to 120 from any starting point, and read and write those numbers. It is timed across 5 sections, gives the exact wording to use where the wording carries the mathematics, names 3 misconceptions with the teaching move that addresses each, and ends with an exit ticket and a printable worksheet with its answer key.
- Grade:
- Grade 1
- Length:
- 40 minutes
- Standard:
- 1.NBT.A.1
Grade 1 · Number & Operations in Base Ten
1.NBT.A.1
Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.
Objective
Students will be able to count to 120 from any starting number and write the numerals correctly.
Students are successful when they can
- Counts on from any number below 120 without restarting.
- Crosses 99 to 100 and 109 to 110 correctly.
- Writes three-digit numerals to 120 without inserting extra zeros.
What you need
- A 120 chart for display and one per pupil
- Counters to mark positions on the chart
- Number cards for starting points
- The printable practice sheet linked at the end of this plan
The lesson
Warm-up — where does the pattern start?
5 min- Count from 21 to 35 together, then from 61 to 75.
- Ask what is the same about the two counts. The ones digits do the same thing, and only the decade word changes.
Teach — crossing the hundred
12 min- Count together from 95. Stop at 99 and ask what comes next before saying it.
- Write 100. Point out that 99 has nine tens and nine ones, and both are full, so a new column is needed.
- Continue to 110 on the chart, pointing at each. The names — one hundred and one, one hundred and two — follow a rule with no exceptions.
- Stop at 109 and ask for the next. This is the second hard join, and it catches more pupils than 99 does.
- Write a few numerals: 101, 110, 120. Say each aloud and ask how many digits. One hundred and one is not 1001.
“After ninety-nine the pattern does not break — it gets easier. Everything past a hundred is just a hundred and a number you already know.”
Guided practice — start anywhere
11 min- Pairs draw a starting card and count on ten numbers, taking turns.
- Include starts at 88, 96 and 107 so both hard joins come up repeatedly.
- The partner tracks on the 120 chart and stops them at any slip.
Independent practice
9 min- Students complete a counting to 120 page.
- Look for 1001 written for one hundred and one — that is a writing error with a different cause from a counting error.
Close
3 min- Go round the room counting on from 112, one number each.
- Finishing past 120 is fine and worth letting happen.
What goes wrong, and why
Each of these is a reasoning error rather than carelessness. The fix addresses the reasoning.
Counts 99, 200.
Why: Nine is full in both columns, and the next 'big' number word available is two hundred. The pupil knows something has to change and picks the wrong change.
Fix: Show it on the chart with the hundreds column. Ninety-nine plus one adds one to the ones, which fills the tens, which fills the hundreds — one hundred, not two.
Counts 108, 109, 200 or 109, 110 as 'one hundred ten' written 10010.
Why: The spoken name is being transcribed piece by piece: 'one hundred' as 100, 'ten' as 10.
Fix: Build 110 as one hundred flat and one ten rod, then write it. Three digits, because there are three columns, and the zero holds the empty ones.
Refuses to count past 100 because 'the chart stops'.
Why: The hundred chart has been the world's boundary. Nothing has suggested numbers continue past the last square.
Fix: Use a 120 chart from the start of Grade 1. The extra two rows cost nothing and stop the boundary from forming.
If they are not there yet
- Work to 100 securely before crossing it, and practise 88 to 102 as a single stretch rather than the whole range.
- Keep the chart in front of them and let them point. Reading the pattern off the chart is how the pattern gets memorised.
If they finish early
- Count on by tens from a number past 100 and watch which digit changes.
- Count backwards from 120 across both hard joins.
- Write the numbers ten more and ten less than a given number without counting.
Exit ticket
Write the next four numbers after 98. Then write the number one hundred and twelve.
What to look for: 99, 100, 101, 102 and 112. '200' after 99 is the hundreds-carry error; '10012' is a transcription error. They need different responses.
Printable practice for 1.NBT.A.1
Free to print and copy, answer key included. Each sheet can generate a fresh set of problems for a retake.
- Count to 60Write the missing numbers.
- Count to 100Write the missing numbers.
Questions about Counting and Writing to 120
How long does the Counting and Writing to 120 lesson take?
40 minutes, split across 5 timed sections: warm-up 5 min, teach 12 min, guided practice 11 min, independent practice 9 min, close 3 min. The minutes are stated per section and add up to the stated length, so the plan can be cut or extended at a section boundary rather than abandoned halfway.
Which standard does Counting and Writing to 120 teach?
CCSS.MATH.CONTENT.1.NBT.A.1 — 1.NBT.A.1, Number & Operations in Base Ten for Grade 1: “Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral.” In plain terms, count to 120 from any starting point, and read and write those numbers.
What do I need to teach this lesson?
A 120 chart for display and one per pupil, counters to mark positions on the chart, number cards for starting points and the printable practice sheet linked at the end of this plan. Everything listed is either ordinary classroom equipment or a free printable from this site — there is nothing to buy and nothing to prepare beyond photocopying.
What mistakes should I expect in this lesson?
Three, each a reasoning error rather than carelessness: counts 99, 200; counts 108, 109, 200 or 109, 110 as 'one hundred ten' written 10010 and refuses to count past 100 because 'the chart stops'. The plan gives the thinking behind each one and the teaching move that addresses the thinking rather than the symptom.
How do I know whether the lesson worked?
The exit ticket asks: “Write the next four numbers after 98. Then write the number one hundred and twelve.” 99, 100, 101, 102 and 112. '200' after 99 is the hundreds-carry error; '10012' is a transcription error. They need different responses. That tells you whether the class needs a reteach or a thirty-second conversation before you plan tomorrow.
Is there a worksheet to go with Counting and Writing to 120?
Yes — 2 printable 1.NBT.A.1 worksheets, linked at the end of the plan and free like the rest of the site. Each one comes with an answer key and 25 versions, so the practice after the lesson can be a different paper on every desk.
Is Counting and Writing to 120 free to use?
Yes. The plan, its printables and their answer keys are free to read, print and photocopy for your own class, with no account and no email capture. It was last reviewed on 5 September 2026. Please do not resell it or republish it as your own.
Last reviewed 2026-09-05. Aligned to 1.NBT.A.1 of the Common Core State Standards for mathematics.