KS2 SATs: 10 most common SATs maths mistakes and how to fix them
We spoke to Darryl, an ex-SATs examiner, about the 10 most common SATs maths mistakes and how to fix them, in preparation for the year 6 SATs.
When the KS2 SATs are around the corner, it's important to be aware of the common mistakes year 6s can make on the maths test. Learning by Questions' very own content author, Darryl Keane, has 15 years of teaching experience and marked the KS2 maths SATs papers for Pearson on behalf of the Standards and Testing Agency. In this blog, he shares the 10 most common SATs mistakes to work on with your year 6s.
For a deeper delve into the KS2 SATs, our Ultimate Guide to SATs has got you covered, including further info on access arrangements.
10 most common SATs maths mistakes, at a glance
Calculating with multiples of 10, 100 and 1,000
Column subtraction
‘How many more…’ and ‘find the difference’ questions
Unfamiliar representations of fractions
Explanations
Interpreting division
Adding fractions
Converting units of measure
Pictograms
Shape
1. Calculating with multiples of 10, 100 and 1,000
Scaling answers accurately is still a common problem for many pupils. This is especially true when more than one number in a calculation is a multiple of 10 or when the product of the related fact is a multiple of 10 (e.g. 60 x 500).
The ex-marker's tip: Children need to have a secure understanding of place value to be able to multiply or divide by 10, 100 and 1,000 as well as being secure with scaling known facts.
Calculating multiples revision resources from Learning by Questions:
Multiply and Divide Numbers Including Decimals by 10, 100 and 1,000
Practise Multiplying Mentally Using Known Table Facts
2. Column subtraction
Column subtraction - a minefield of misconceptions! When using column subtraction, children may find the difference between the digits in a column instead of re-grouping. Errors also commonly occur when there are place-holding zeros in the larger number.
The ex-marker's tip: Watch out for children taking the exchanged 1 straight to the column they are working on, missing interim exchanges.
Column subtraction revision resource from Learning by Questions:
Subtract Numbers up to 3 Digits using the Column Method
3. ‘How many more…’ and ‘Find the difference…’ questions
Children are frequently asked to find the difference between two values, but many children struggle to recognise these questions as requiring subtraction, especially out of lesson context.
The ex-marker's tip: Bar models are particularly useful at helping children to see that they need to use subtraction.
Find the difference revision resource from Learning by Questions:
Subtract Numbers with More Than 4 Digits
Find out more: Read our top grammar mistakes blog
4. Unfamiliar representations of fractions
While children may confidently recognise ¾ when dealing with basic shapes, they might face challenges with unfamiliar shapes or patterns. In such cases, they may attempt to draw horizontal or vertical lines or simply shade in three parts of any shape presented to them. Interestingly, this is still a big issue in year 6 classrooms throughout the country in the context of a number line: just 32.4% of pupils in year 6 could answer correctly on their first attempt.
The ex-marker's tip: It's crucial for children to firmly grasp the concept that the denominator represents 'equal parts' to effectively apply their knowledge.
Unit and non-unit fractions revision resources from Learning by Questions:
Understand Unit and Non-Unit Fractions
Recognise Unit and Non-Unit Fractions on a Number Line
Related content:
The ultimate guide to KS2 SATs: dates, papers, revision and results
2025 KS2 SATs results analysis
KS2 SATs 2025: Maths paper analysis
5. Explanations
There’s usually at least one (often dreaded) ‘explain your answer’ question where pupils who struggle to articulate themselves when writing can get themselves into a mess. Pupils often spend a long time attempting to achieve one mark with a wordy explanation full of irrelevant details.
The ex-marker's tip: Usually, proving a statement is incorrect using the correct mathematics is good enough. But watch out for incorrect maths: if there’s anything at all mathematically incorrect in the explanation bubble, the mark won’t be awarded (for example, using symbols as part of jottings such as 1 = 5, so 2 = 10).
Explanation and reasoning revision resource from Learning by Question
Reasoning: Find or Explain the Mistake
6. Interpreting division
Y6 pupils often recognise that a particular word problem requires division. However, many won’t go on to gain any marks - even after a correct calculation - as a result of not interpreting their answer accurately to complete their method (for example, they’ll not round their answer up or down to the nearest whole number).
The ex-marker's tip: Keep an eye out for pupils copying the wrong part of their algorithm to the answer box or omitting some of the digits, losing them marks.
Interpreting division revision resources from Learning by Questions:
All of Learning by Questions' division resources contain opportunities for pupils to interpret the answers to their division calculations correctly, receiving feedback where appropriate.
7. Adding fractions
Another classic: children add the numerators and the denominators.
The ex-marker's tip: This one's a stubborn misconception that takes a bit of practice to get right. You can build pupils' confidence with fractions by using Learning by Questions' revision sets.
Adding fractions revision resource from Learning by Questions:
Add and Subtract Fractions with the Same Denominator
8. Converting units of measure
This links to number 1 on the list, but with the additional difficulty of knowing facts such as how many mm are in a cm.
The ex-marker's tip: Children need to know the equivalences, then know whether to multiply or divide.
Converting units of measure revision resource from Learning by Questions:
Convert Between Different Units of Measure
9. Pictograms
A favourite on tests: the pictogram! Children enjoy them as they are often perceived as ‘easy’ questions. However, many children come unstuck on these questions if they don’t correctly interpret the value of one symbol. As this is located under or next to the main data table, children often miss it and consequently get the questions wrong.
The ex-marker's tip: Make sure the children are reading the question carefully. Finding the key is the most important part!
Pictograms revision resource from Learning by Questions:
Read and Interpret Data using Pictograms
10. Shape Struggles
Many year 6 children still only identify regular shapes in standard orientations. A great example of this is the rotated square. Even though it is exactly the same shape with 4 right angles, children often see it as a kite.
The ex-marker's tip: Getting to grips with this topic takes regular practice with a wide range of orientations.
Shape revision resources from Learning by Questions:
Compare and Classify Geometric Shapes
How to avoid common year 6 maths mistakes
Using past papers
Challenge the children to mark a past paper that’s filled with deliberate mistakes, matching up with common misconceptions. Spotting and explaining the error will boost their critical analysis skills for the maths SATs papers.
Find out more: Which SATs papers to use and when
Weave reasoning routines into your weekly plan
To address those dreaded explanation questions, it’s a good idea to dedicate time each week to explaining mathematical thinking. Using sentence stems like “this can’t be right because…” or “this is correct because…” will build the children’s confidence in answering these tricky questions.
In-class feedback
Catching misconceptions during class, while children are working through a problem, is crucial for mastery learning. However, manually providing this continuous, formative feedback to 30+ pupils is often impractical. With SATs Springboard from Learning by Questions, every pupil receives precise, personalised feedback on their answers immediately. This ensures mistakes are addressed before they become habits, without a mountain of marking for you!