You will learn
- Read three-digit numbers.
- Write three-digit numbers in digits.
- Write three-digit numbers in words.
- Say what the numbers between hundreds are.
Version 0.2 · expanded edition · built from cited public sources Content is based on the official frameworks and sources listed under Sources and standards. No official endorsement is claimed. Written in the style of common primary school assessments. No exam result is promised.
Student lesson
- Three-digit numbers go from 100 to 999.
- Each digit has a place: hundreds, tens, ones.
- We can write the number in words.
- 999 + 1 = 1,000.
Words to know
A number from 100 to 999.
A symbol 0 to 9.
Where a digit sits in a number.
Written with letters.
1. Discover: a bus ticket number
A bus ticket says 346. How do you say that number? What does each digit tell you?
2. Understand: three-digit numbers
A three-digit number has hundreds, tens and ones. In 346: 3 hundreds, 4 tens and 6 ones. We say “three hundred and forty-six”.
When there is no tens, we write 0: 304 is three hundred and four. When there are no ones: 340 is three hundred and forty.
The biggest three-digit number is 999. One more is 1,000.
Idea 1: Three digits
A three-digit number has a hundreds digit, a tens digit and a ones digit. In 346 the digits are 3, 4 and 6.
Idea 2: In words
346 is three hundred and forty-six. 205 is two hundred and five. A zero in the tens place means no tens.
Idea 3: Between the hundreds
Numbers between 300 and 400 start with 3. One more than 999 is 1,000.
Why zero? Zero holds a place so that 205 is not mixed up with 25.
3. Worked examples
Example 1 (I show you): Digits to words
Write 346 in words.
- 3 hundreds: three hundred.
- 46: forty-six.
Answer: Three hundred and forty-six
Example 2 (We do it together): Words to digits
Write two hundred and five in digits.
- 2 hundreds, 0 tens, 5 ones.
Answer: 205
Example 3 (You try): One less
What number is one less than 400?
Show the steps and answer
- Count back from 400.
Answer: 399
Did you know?
The number 1,000 has four digits. It is the first four-digit number.
Why this matters
We read three-digit numbers on prices, bus numbers, dates and distances.
4. Explore: say it and write it
You need paper and a pencil.
- Write 245 in digits and in words.
- Say 408 and write it in words.
- Write six hundred and twelve in digits.
- Say which digit is in the tens place in 721.
Think about it: what did you notice?
245 is two hundred and forty-five. 408 is four hundred and eight. 612. The tens digit in 721 is 2.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- The hundreds digit is ___.
- ___ in words is ___.
- One more than ___ is ___.
- The zero holds the ___ place.
Guided practice
Question 1. Read 346.
three hundred and forty-six.
Question 2. Write two hundred and five.
205.
Question 3. What number is one more than 999?
1,000.
Independent practice
Level 1: Start
- Write 450 in words.
- Write seven hundred and sixty-one in digits.
- What is the tens digit in 592?
- Write the number: 3 hundreds, 0 tens and 8 ones.
- What number is one less than 400?
Level 2: Grow
- Write 830 in words.
- What is the ones digit in 247?
- Write 6 hundreds, 5 tens and 1 one.
Level 3: Stretch
- What is 1 more than 899?
- Which is bigger: 459 or 495?
- Ana writes four hundred and six as 46. What is wrong?
Answers are in the answer key below. Try first, then check.
6. Apply: everyday mathematics
A school has three hundred and twelve pupils. Write the number of pupils.
Show a sample answer
312.
Another one. A library has three hundred and twelve books. Write the number and say its hundreds digit.
Show a sample answer
312; the hundreds digit is 3
7. Common mistakes
Fix: Hundreds, then tens (0), then ones: 305.
Fix: Write 0 for no tens: 406.
Fix: Say five hundred and ninety-two.
8. Lesson summary and revision card
- I can read three-digit numbers.
- I can write them in digits.
- I can write them in words.
- I can name the digits.
9. Check and master
Answer all 14 questions. You will see feedback after each one.
Your result appears here after you answer every question.
10. Key takeaways
- Three digits: hundreds, tens and ones.
- A 0 holds a place.
- Read and write numbers in digits and words.
11. Next lesson
Next lesson: Hundreds, tens and ones. Keep going with the next idea in this course.
Exam practice
These questions are written in the style of common school and international primary assessments. Try them on your own, without looking back. Then check your answers in the marking guide. The marks are shown in brackets.
- Write 340 in words. [1 mark]
- Write seven hundred and two in digits. [1 mark]
- What is the tens digit in 485? [1 mark]
- What is one less than 500? [1 mark]
- Ben writes three hundred and five as 35. Explain his mistake. [3 marks]
Total: 7 marks.
Marking guide and model answers
- three hundred and forty [1]
- 702 [1]
- 8 [1]
- 499 [1]
- 35 has no hundreds [1]; there are 0 tens [1]; the number is 305 [1]
Score guide: 6 to 7 = secure. 5 to 5 = nearly there, revise the parts you missed. Under 5 = work through the lesson again with a grown-up.
Printable worksheet
- Write 450 in words.
- Write seven hundred and sixty-one.
- Tens digit in 592?
- 3 hundreds, 0 tens, 8 ones?
- One less than 400?
- Write 215 in words.
- Hundreds digit of 783?
- 300 + 40 + 6 = ___.
- What comes after 999?
- Write 8 hundreds and 3 ones.
Homework
Find three-digit numbers on bus tickets, prices or houses. Write three in words.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| Write 450 in words. | four hundred and fifty | 2 |
| Write seven hundred and sixty-one. | 761 | 2 |
| Tens digit in 592? | 9 | 2 |
| 3 hundreds, 0 tens, 8 ones? | 308 | 2 |
| One less than 400? | 399 | 2 |
| Total | 10 |
Practice answers: Worksheet: 1 four hundred and fifty; 2 761; 3 9; 4 308; 5 399.
Quiz answers: 1 A, 2 B, 3 C, 4 A, 5 B, 6 A, 7 B, 8 C, 9 A, 10 B, 11 C, 12 A, Challenge 1 C, Challenge 2 C.
Extra worksheet answers (items 6 onward): 6 two hundred and fifteen; 7 7; 8 346; 9 1,000; 10 803.
Independent practice answers. Level 1: 1 four hundred and fifty; 2 761; 3 9; 4 308; 5 399. Level 2: 1 eight hundred and thirty; 2 7; 3 651. Level 3: 1 900; 2 495; 3 It has no hundreds digit. The number is 406..
Mastery and remediation
| Objective | Bronze (Developing) | Silver (Proficient) | Gold (Advanced) |
|---|---|---|---|
| O1 Read three-digit numbers | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O2 Write three-digit numbers in digits | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O3 Write three-digit numbers in words | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
| O4 Say what the numbers between hundreds are | Shows this with help from an adult or a picture | Does this independently and explains how they know | Explains it clearly and uses it in a new situation |
Courseversity badge thresholds (overall quiz score): Gold = 90–100%; Silver = 80–89.9%; Bronze = 70–79.9%. A badge is never a full record of progress.
If a learner struggles
- Find the misconception: Writing three hundred and five as 3005. Hundreds, then tens (0), then ones: 305.
- Explain another way: use real objects first, then pictures.
- Show a simpler example: Use place value cards (100, 40, 6) to build 146.
- Guided practice: work through one example together and let the learner try the next one.
- Reassess: use the quiz again or the worksheet.
- Move on when the learner shows Silver-level evidence independently.
For parents and guardians
In this lesson your child reads and writes three-digit numbers in digits and words. You do not need to be good at mathematics to help.
- Read house, bus and price numbers aloud.
- Write a number on paper and ask for the hundreds digit.
- Ask: what is one more? One less?
- Ask “how do you know?” after each answer, and listen.
- Praise effort, not only right answers. Mistakes are how we learn.
- Ten to fifteen minutes a day is better than one long session.
Teacher package
1–5. Objectives, prerequisites, materials, preparation, duration
Lesson objectives. Learners will: read three-digit numbers; write three-digit numbers in digits; write three-digit numbers in words; say what the numbers between hundreds are.
Prerequisite knowledge. Lessons 1 and 2.
Materials. Counters (stones, seeds or bottle tops), paper, pencils, board or chalkboard. Low-resource options: use stones, seeds, sticks, bottle tops or drawings in the sand or on the board instead of printed materials.
Preparation. Gather the counters and draw the example pictures on the board before the lesson.
Suggested duration. 45–60 minutes. It can be split into two shorter sessions.
6–9. Teaching procedure, explanation notes, guided and independent activities
Introduction (5 min). Start with the Discover situation and let learners suggest ideas before you teach.
Explanation (10 min). Teach the Understand section with real objects first, then pictures, then symbols and words.
Guided activity (10 min). You need paper and a pencil. Learners follow the Explore steps in pairs.
Independent activity (10 min). Learners complete the independent practice and the worksheet.
Assessment and reflection (5 min). Ask each learner to say one thing they learned and how they know it.
Key questions. What is the hundreds digit? What does the zero mean? How do you say it?
Teacher explanation notes. Use the concrete, pictorial, abstract order: real objects first, then pictures, then symbols and words. Return to real objects whenever a learner needs support.
10–12. Differentiation, formative assessment, common misconceptions
Support. Use real objects and work with a partner; say each step aloud together. Extension. Ask learners to make up their own example and explain it to a partner.
Formative assessment. Listen to learner explanations, ask “how do you know?”, and check the independent work.
Misconceptions. Writing three hundred and five as 3005. Hundreds, then tens (0), then ones: 305.
13–15. Assessment questions, answer keys, marking scheme
Use the quiz and worksheet on this page. The 7-mark exam practice scheme, the 10-mark scheme and all answers are in the answer sections above. Re-check every answer and the marking scheme before publication.
16–19. Remediation, enrichment, homework, teacher reflection
Remediation. Use place value cards (100, 40, 6) to build 146. Enrichment. Invite learners to find or create three more examples at home or in the classroom and explain them. Homework. See above.
Teacher reflection. After teaching, record: which concepts learners understood; which misconceptions occurred; which activities worked; which learners need more practice; and what to improve next time.
Sources and standards
This lesson is based on the sources below, and no official endorsement is claimed. Reference starting points named in the Courseversity standard: Common Core State Standards for Mathematics, Cambridge Primary and the IB Primary Years Programme. Where a standard code is named, it points to the official framework.
Official standards for this topic area. Common Core State Standards for Mathematics (official site): Grade 2 » Number & Operations in Base Ten. These pages list the standards that cover this topic area; read them alongside the lesson.
Research used to shape this lesson. Common Core 2.NBT.A.3 (read and write numbers to 1000); Cambridge Primary Mathematics Stage 2. These sources informed the lesson.