You will learn
- Multiply a number by 10 and 100.
- Multiply by multiples of ten like 20 and 30.
- Use a basic fact and add zeros.
- Solve problems with tens.
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
- Use a basic fact.
- Add a zero for each ten.
- Times 10 adds one zero.
- Times 100 adds two zeros.
Words to know
10, 20, 30 …
A fact like 3 × 4.
The digit 0.
Groups of ten.
1. Discover: bundles of ten
One bundle has 10 sticks. 6 bundles are 60 sticks. What are 6 bundles of 30 sticks?
2. Understand: multiplying by multiples of ten
Use a basic fact and add zeros.
- 3 × 10 = 30 (3 tens).
- 4 × 20 = 4 × 2 tens = 8 tens = 80.
- 6 × 30 = 6 × 3 tens = 18 tens = 180.
- 7 × 100 = 700.
- 5 × 40 = 5 × 4 tens = 20 tens = 200.
Think “how many tens?”, then write the answer.
Idea 1: Times 10
8 × 10 = 80. Each digit moves one place to the left.
Idea 2: Multiples of ten
3 × 20: 3 × 2 = 6, then add a zero: 60. 5 × 30 = 15 tens = 150.
Idea 3: Times 100
6 × 100 = 600. 4 × 60: 4 × 6 = 24, add a zero: 240.
Why add zeros? We are counting groups of ten or hundred.
3. Worked examples
Example 1 (I show you): Times 10
8 × 10 = ?
- 8 tens.
Answer: 80
Example 2 (We do it together): Times 20
3 × 20 = ?
- 3 × 2 = 6, add a zero.
Answer: 60
Example 3 (You try): Times 60
4 × 60 = ?
Show the steps and answer
- 4 × 6 = 24, add a zero.
Answer: 240
Did you know?
Times 10 does not add a zero to decimals, but for whole numbers it works.
Why this matters
Multiples of ten help with money and measures.
4. Explore: tens bundles
You need paper and a pencil.
- Write 4 × 2 = 8, then 4 × 20 = 80.
- Write 6 × 3 = 18, then 6 × 30 = 180.
- Write 5 × 4 = 20, then 5 × 40 = 200.
- Do 9 × 50.
Think about it: what did you notice?
9 × 5 = 45 tens = 450.
5. Practise
Say it in a sentence
Use these starters when you talk about the lesson. Say them out loud.
- The basic fact is ___.
- Then I add ___ zero(s).
- The answer is ___.
- ___ tens make ___.
Guided practice
Question 1. 3 × 10?
30.
Question 2. 6 × 30?
180.
Question 3. 7 × 100?
700.
Independent practice
Level 1: Start
- 8 × 10
- 3 × 20
- 5 × 30
- 6 × 100
- 4 × 60
Level 2: Grow
- 4 × 10
- 2 × 30
- 3 × 100
Level 3: Stretch
- 8 × 70
- 6 × 40
- Ana says 5 × 20 = 10. What is wrong?
Answers are in the answer key below. Try first, then check.
6. Apply: everyday mathematics
A farmer packs 30 oranges in each of 6 sacks. How many oranges?
Show a sample answer
180 oranges.
Another one. A pack has 20 pencils. How many pencils are in 6 packs?
Show a sample answer
120 pencils
7. Common mistakes
Fix: Count the tens: 18 tens = 180.
Fix: Add a zero for each ten.
Fix: Times 10 adds one zero. Times 100 adds two.
8. Lesson summary and revision card
- I can multiply by 10 and 100.
- I can multiply by 20, 30 and so on.
- I can use a basic fact.
- I can solve problems with tens.
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
- Use the basic fact.
- Count the tens.
- Add the zeros.
11. Next lesson
Next lesson: Multiplication strategies. 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.
- 8 × 10 = ? [1 mark]
- 3 × 20 = ? [2 marks]
- 5 × 30 = ? [2 marks]
- 6 × 100 = ? [1 mark]
- Ali says 4 × 60 = 24. Is he right? Explain. [3 marks]
Total: 9 marks.
Marking guide and model answers
- 80 [1]
- 3 × 2 = 6 [1]; 60 [1]
- 5 × 3 = 15 [1]; 150 [1]
- 600 [1]
- No [1]. 4 × 6 = 24 [1]. Add a zero to get 240 [1].
Score guide: 8 to 9 = secure. 6 to 7 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.
Printable worksheet
- 8 × 10
- 3 × 20
- 5 × 30
- 6 × 100
- 4 × 60
- 3 × 10 =
- 4 × 20 =
- 6 × 30 =
- 7 × 100 =
- 5 × 40 =
Homework
Use bundles of ten sticks to show 4 × 30. Write the answer.
Answer key and marking scheme
| Question | Expected response | Marks |
|---|---|---|
| 8 × 10 | 80 | 2 |
| 3 × 20 | 60 | 2 |
| 5 × 30 | 150 | 2 |
| 6 × 100 | 600 | 2 |
| 4 × 60 | 240 | 2 |
| Total | 10 |
Practice answers: Worksheet: 1 80; 2 60; 3 150; 4 600; 5 240.
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 30; 7 80; 8 180; 9 700; 10 200.
Independent practice answers. Level 1: 1 80; 2 60; 3 150; 4 600; 5 240. Level 2: 1 40; 2 60; 3 300. Level 3: 1 560; 2 240; 3 She forgot the zero. 5 × 2 = 10, so 5 × 20 = 100..
Mastery and remediation
| Objective | Bronze (Developing) | Silver (Proficient) | Gold (Advanced) |
|---|---|---|---|
| O1 Multiply a number by 10 and 100 | 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 Multiply by multiples of ten like 20 and 30 | 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 Use a basic fact and add zeros | 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 Solve problems with tens | 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 6 × 30 as 18. Count the tens: 18 tens = 180.
- Explain another way: use real objects first, then pictures.
- Show a simpler example: Use ten-sticks and make groups of tens.
- 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 multiplies by 10, 100 and multiples of ten. You do not need to be good at mathematics to help.
- Use coins of 10 naira.
- Ask: what is the basic fact?
- Count in tens together.
- 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: multiply a number by 10 and 100; multiply by multiples of ten like 20 and 30; use a basic fact and add zeros; solve problems with tens.
Prerequisite knowledge. Lessons 3 and 4.
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 basic fact? How many zeros to add?
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 6 × 30 as 18. Count the tens: 18 tens = 180.
13–15. Assessment questions, answer keys, marking scheme
Use the quiz and worksheet on this page. The 9-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 ten-sticks and make groups of tens. 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 3 » Operations & Algebraic Thinking; Grade 3 » 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 3.NBT.A.3 (multiply by multiples of 10); Cambridge Primary Mathematics Stage 3 (multiplication). These sources informed the lesson.