Writing decimals

Primary EducationGrade 4MathematicsCV-PRI-G04-MATH-FRA-U02-L0445–60 min

You will learn

  • Read decimals aloud.
  • Write decimals in digits.
  • Link decimals to fractions.
  • Write mixed-number decimals.

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

The lesson in 60 seconds

  1. Read the whole part, then “and”, then the parts.
  2. Say tenths and hundredths clearly.
  3. Match fractions with denominators 10 and 100 to decimals.
  4. Write mixed numbers as decimals.

Words to know

decimal
A number with a point.
point
Said between ones and tenths.
digit
0 to 9.
mixed number
Whole and fraction.

1. Discover: saying decimals

How do you say 3.25? Is it three point twenty-five or three point two five?

2. Understand: writing decimals

  • 0.25 = twenty-five hundredths = 25/100.
  • 3.25 = three and twenty-five hundredths = 3 25/100.
  • We can say “three point two five”.
  • 0.8 = eight tenths = 8/10.

Idea 1: Tenths

Six tenths is 0.6. Two and four tenths is 2.4.

Idea 2: Hundredths

Seven hundredths is 0.07. 25/100 = 0.25.

Idea 3: Words

1.05 is “one and five hundredths”. 0.5 = 5/10 = 1/2.

Why the zero in 0.07? It holds the tenths place.

Remember: Say the whole part, “point”, then each digit, or say the fraction name.

3. Worked examples

Example 1 (I show you): Write

Six tenths

  1. One place after the point.

Answer: 0.6

Example 2 (We do it together): Write

Seven hundredths

  1. Two places: 0.07.

Answer: 0.07

Example 3 (You try): Fraction

0.5

Show the steps and answer
  1. 5 tenths.

Answer: 5/10 = 1/2

Did you know?

The word “and” marks the decimal point when we read a number.

Why this matters

Reading and writing decimals correctly avoids costly mistakes with money and measures.

4. Explore: say and write

You need paper.

  1. Write 0.25.
  2. Say it two ways.
  3. Write 3 25/100 as a decimal.
  4. Write eight tenths.
Think about it: what did you notice?

3.25; 0.8.

5. Practise

Say it in a sentence

Use these starters when you talk about the lesson. Say them out loud.

  • The whole part is ___.
  • The tenths digit is ___.
  • The hundredths digit is ___.
  • I write it as ___.

Guided practice

Question 1. 25/100 as a decimal?

0.25.

Question 2. 3 25/100 as a decimal?

3.25.

Question 3. Eight tenths?

0.8.

Independent practice

Level 1: Start

  1. Write six tenths
  2. Write seven hundredths
  3. Write 2 and 4 tenths
  4. Write 0.5 as a fraction
  5. Write 1.05 in words

Level 2: Grow

  1. 9/10 as a decimal
  2. 4 and 5 tenths
  3. 0.03 as a fraction

Level 3: Stretch

  1. 12 8/100 as a decimal
  2. 0.36 as a fraction in lowest terms
  3. Ana writes 2 and 4 hundredths as 2.4. What is wrong?

Answers are in the answer key below. Try first, then check.

6. Apply: everyday mathematics

A rope is two and three tenths metres. Write it as a decimal.

Show a sample answer

2.3 m.

Another one. A race takes 12 seconds and 5 hundredths. Write the time as a decimal.

Show a sample answer

12.05 seconds

7. Common mistakes

Mistake: Writing seven hundredths as 0.7.
Fix: 0.07.
Another mistake: Writing seven hundredths as 0.7.
Fix: It is 0.07.
Another mistake: Leaving out the zero place holder.
Fix: 2 and 4 hundredths is 2.04.

8. Lesson summary and revision card

I can…

  • I can read decimals aloud.
  • I can write decimals in digits.
  • I can link decimals to fractions.
  • I can write mixed-number decimals.

9. Check and master

Answer all 14 questions. You will see feedback after each one.

1. 25/100 as a decimal is…

2. 3 25/100 as a decimal is…

3. Eight tenths is…

4. Seven hundredths is…

5. 0.5 as a fraction is…

6. 63/100 as a decimal is…

7. 4 7/10 as a decimal is…

8. Nine hundredths is…

9. Five and six tenths is…

10. 1.25 in words is…

11. 0.75 as a fraction over 100 is…

12. 6 3/100 as a decimal is…

Challenge 1. Two and three tenths is…

Challenge 2. 3 and 5 tenths and 2 hundredths is…

Your result appears here after you answer every question.

10. Key takeaways

  • Say the point.
  • Match the place.
  • Decimals are fractions.

11. Next lesson

Next lesson: Comparing decimals. 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.

  1. Write six tenths as a decimal. [1 mark]
  2. Write two and four tenths as a decimal. [1 mark]
  3. Write 0.5 as a fraction. [2 marks]
  4. Write 1.05 in words. [3 marks]
  5. Ben writes seven hundredths as 0.7. Is he right? Explain. [3 marks]

Total: 10 marks.

Marking guide and model answers
  1. 0.6 [1]
  2. 2.4 [1]
  3. 5 tenths = 5/10 [1]; 1/2 [1]
  4. one [1]; and [1]; five hundredths [1]
  5. No [1]. Hundredths are in the second place [1]. It is 0.07 [1].

Score guide: 9 to 10 = secure. 6 to 8 = nearly there, revise the parts you missed. Under 6 = work through the lesson again with a grown-up.

Printable worksheet

  1. Six tenths
  2. Seven hundredths
  3. 2 and 4 tenths
  4. 0.5 as a fraction
  5. Eight tenths
  6. 25/100 as a decimal is
  7. 3 25/100 as a decimal is
  8. Eight tenths is
  9. Seven hundredths is
  10. 0.5 as a fraction is

Homework

Write ten decimals in digits and words.

Answer key and marking scheme

Question Expected response Marks
Six tenths 0.6 2
Seven hundredths 0.07 2
2 and 4 tenths 2.4 2
0.5 as a fraction 5/10 2
Eight tenths 0.8 2
Total 10

Practice answers: Worksheet: 1 0.6; 2 0.07; 3 2.4; 4 5/10; 5 0.8.

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 0.25; 7 3.25; 8 0.8; 9 0.07; 10 5/10.

Independent practice answers. Level 1: 1 0.6; 2 0.07; 3 2.4; 4 5/10 = 1/2; 5 one and five hundredths. Level 2: 1 0.9; 2 4.5; 3 3/100. Level 3: 1 12.08; 2 36/100 = 9/25; 3 Hundredths need two places: 2.04..

Mastery and remediation

Objective Bronze (Developing) Silver (Proficient) Gold (Advanced)
O1 Read decimals aloud 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 decimals 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 Link decimals to fractions 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 Write mixed-number decimals 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

  1. Find the misconception: Writing seven hundredths as 0.7. 0.07.
  2. Explain another way: use real objects first, then pictures.
  3. Show a simpler example: Match words to digits.
  4. Guided practice: work through one example together and let the learner try the next one.
  5. Reassess: use the quiz again or the worksheet.
  6. Move on when the learner shows Silver-level evidence independently.

For parents and guardians

In this lesson your child reads and writes decimals in digits and words. You do not need to be good at mathematics to help.

  • Read price tags aloud.
  • Ask: how many places after the point?
  • Say “and” for the point.
  • 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 decimals aloud; write decimals in digits; link decimals to fractions; write mixed-number decimals.

Prerequisite knowledge. Lessons 1 to 3.

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. 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. How many places after the point? Do I need a zero?

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 seven hundredths as 0.7. 0.07.

13–15. Assessment questions, answer keys, marking scheme

Use the quiz and worksheet on this page. The 10-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. Match words to digits. 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 4 » Number & Operations—Fractions; Grade 4 » 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 4.NF.C.5 and 4.NF.C.6; Cambridge Primary Mathematics Stage 4 (reading and writing decimals). These sources informed the lesson.

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