Written methods with decimals – Year 8 maths lesson
Lesson 6 of 35 in the Year 8 maths course
UK version. UK school years, UK spelling and pounds (£). · US Math Department
A complete 45-minute lesson for Year 8 (ages 12–13) that runs on this page – at school or at home. Every answer is marked straight away, with a worked explanation.
- Time
- 45 minutes + 20 min homework
- Year
- Year 8 (ages 12–13)
- You need
- Paper, a pencil and this page
- Marked
- Instantly, with explanations
For parents: how to use this lesson
You don't need to know this topic yourself. The lesson explains each step on screen, one tidy step at a time. Every answer is marked straight away with a worked explanation, so you never have to mark anything.
- Read what your child will learn and the big ideas together.
- Press Start the lesson below and sit with your child for the teaching and the worked examples (about 19 minutes).
- Let them do the practice on their own. They choose Getting started, On track or Challenge – start on On track and move up after a few right in a row.
- Finish with the exit ticket and the talk question: “Why does 4.8 ÷ 0.6 give the same answer as 48 ÷ 6?”
- Later that day or the next day: the homework (20 minutes), then a practice test.
Watch out for
- Lining up the last digits instead of the decimal points. Line the points up first.
- Dividing 4.8 by 0.6 and getting 0.8. Make the divisor a whole number by multiplying both by 10.
Tip for home: Work out unit prices or shares of a bill with decimals together.
What your child will learn
We are learning to add, subtract, multiply and divide whole numbers and decimals with written methods.
Success looks like
- I can add and subtract decimals.
- I can multiply decimals.
- I can divide by a decimal.
Key words
- decimal place
- a place after the decimal point
- product
- the answer to a multiplication
- quotient
- the answer to a division
- estimate
- a quick check using rounded numbers
What to have ready
- Paper and a pencil
- This page on a computer, tablet or phone
- For the hands-on part: Estimate first, then calculate exactly; compare the two answers.
The big ideas (for the adult)
For adding and subtracting decimals, line up the decimal points and fill empty places with zeros.
To multiply decimals, multiply without the points, then count the decimal places in the question: 0.3 × 0.12 has three, so 36 becomes 0.036.
To divide by a decimal, multiply both numbers by 10, 100… until you divide by a whole number: 4.8 ÷ 0.6 = 48 ÷ 6 = 8.
The lesson, step by step
| Part | Time | How it is checked |
|---|---|---|
| Starter: quick recall | 5 min | Marked by Classfern |
| Teaching input | 10 min | Not assessed, self-checked |
| Worked examples and guided practice | 9 min | Not assessed, marked by Classfern |
| Independent practice | 15 min | Marked by Classfern |
| Plenary and exit ticket | 6 min | Marked by Classfern, self-checked |
Starter, "your turn", practice and exit ticket are marked by Classfern. Worked examples and teaching are not assessed. The hands-on task and the reflection are self-assessed. Explanations in talk are judged by the parent and not recorded.
The lesson
It runs here on the page. No sign-up and no names – progress is kept only in this browser.
Homework and practice at home
20 minutes: 10 practice questions, 3 multiple-choice questions and 2 to remember from earlier work, then a short reflection. New questions every time, all marked instantly.
More practice
More Year 8 maths lessons
- Ordering numbers, decimals and negatives
- Calculating with negative numbers
- Prime factors, HCF and LCM
- Rounding and estimation
- Powers and roots
- BIDMAS: order of operations
- Calculating with fractions
- Units and measures
- Area of triangles, parallelograms and trapeziums
- Circles: circumference, area, arcs and sectors
- Angle facts and parallel lines
- Angles in polygons
- Transformations
- Quadrilaterals and symmetry
- Constructions and loci
- Averages and range
- Scatter graphs and correlation
- Probability
- Relative frequency and expected outcomes
- Algebraic notation
- Substitution
- Simplifying expressions
- Expanding brackets
- Solving linear equations
- Sequences and the nth term
- Straight-line graphs
- Graphs of functions
- Ratio
- One quantity as a fraction or percentage of another
- Percentages
- Direct and inverse proportion
- Speed, density and pressure
- Best buys and exchange rates
- Scale drawings and maps
Curriculum
National Curriculum for England, Year 8: “use the 4 operations, including formal written methods, applied to integers, decimals, proper and improper fractions, and mixed numbers, all both positive and negative”
GCSE subject content N2: “apply the four operations, including formal written methods, to integers, decimals and simple fractions (proper and improper), and mixed numbers – all both positive and negative; understand and use place value (e.g. when working with very large or very small numbers, and when calculating with decimals)”
Contains public sector information licensed under the Open Government Licence v3.0.
Our lessons and questions are our own. They are not written or endorsed by any government department, testing agency or exam board.