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Why It’s So Hard to Measure Maths Skills in Toddlers—and Why It Matters

25 June 2025

6 mins

This blogpost is written by Dr Hanna Weiers and Professor Camilla Gilmore. Dr Hanna Weiers is a Postdoctoral Research Associate for the Centre for Early Mathematics Learning (CEML). Hanna is interested in how children begin to learn and understand mathematical concepts, and how this develops over time. Professor Camilla Gilmore is Professor of Mathematical Cognition and Director of CEML. Camilla’s research focuses on understanding how mathematical thinking develops in children and the factors that influence mathematical learning. This blogpost is edited by Dr Bethany Woollacott.

In this blog post, Hanna and Camilla draw on their recently published literature review exploring the surprising gap in our understanding of how mathematical abilities develop in very young children – specifically two-year-olds. This post reveals the practical and conceptual challenges of assessing maths skills at this age, highlights what researchers have tried so far, and offers three key takeaways for improving our understanding of early mathematics development and how to support it.

A child arranges numbered blocks in order from 0 to 12.

Introduction: The Missing Year in Maths Research

By the age of two, toddlers are already navigating complex ideas about their world – they can stack blocks, follow instructions, and even start to count. Yet, despite decades of research into how children learn maths, there’s a curious blind spot in the field: toddlerhood.

Why is this important? Because this is the age when foundational mathematical thinking begins to emerge. But, if researchers can’t accurately assess those early skills, we risk misunderstanding how mathematical learning emerges. This blog post unpacks why this “toddler gap” exists, what it means for developmental science, and how we might begin to close it.

Why Study Mathematics in 2-Year-Olds?

Most studies on early mathematical development either focus on infants under 12 months or preschoolers aged three and up. Two-year-olds often get left out. This is not because they’re not doing anything interesting – on the contrary – they’re right at the point where they are beginning to understand crucial concepts like quantity, comparison, and order.

So, why are toddlers often left out?

Toddlers are tricky research participants. They’re too active for baby-focused methods like eye-tracking or preferential looking, and they’re too young for the verbal instructions and task compliance needed for preschool measures.

However, as we mentioned above, understanding what mathematical knowledge looks like at age two is key to developing realistic theories of early learning; therefore, despite the challenges of testing this age group, it’s important to develop methods which can effectively assess two-year-olds’ mathematical knowledge.

A Review of Existing Methods

Although the research is scarce, there have been attempts to measure two-year olds’ mathematical learning in the existing literature. Therefore, we reviewed studies which measured basic mathematics skills in two-year-olds, aiming to identify and evaluate which tasks have been used. In the following, we highlight some of the methods we found in our review:

1. Non-symbolic tasks, e.g., comparing which group has more dots.

Such tasks are often too language-dependent. For example, toddlers might not understand the word “more,” leading to misleading results.

2. Counting tasks, e.g., reciting numbers or counting objects.

If toddlers fail on these tasks it is difficult to infer whether this is a competence or performance issue, i.e., does the toddler lack key mathematical knowledge or are they just reluctant or unable to demonstrate it?

3. Cardinality and one-to-one correspondence tasks, e.g., producing or naming sets.

For these tasks, we found evidence of the jingle-jangle fallacy: researchers may use the same task to measure different constructs or different tasks to measure the same construct. For example, asking children to count objects is used by some researchers to assess counting skills, but by others to assess one-to-one correspondence. On the other hand, cardinality understanding may be assessed by either a task in which children create a set of items or by a task in which children select which of two cards have a certain number of items, yet these are likely to draw on different types of understanding and skills.

4. Spontaneous focusing tasks, e.g., do toddlers spontaneously pay attention to numbers and quantities without being prompted to do so?

A challenge with these tasks is capturing spontaneous behaviour and attention to numerosity rather than numerical skill.

5. Arithmetic tasks, e.g., adding or taking away objects from a set.

These have not been used very much with this age group because toddlers are still at the very early stages of development. Some tasks are too language heavy, and others are similar to tasks measuring one-to-one correspondence and cardinality (Bullet point 3. above).

6. Standardised tests, e.g., broader cognitive assessments with specific mathematics items.

These aren’t often tailored to this age and are unable to provide sensitive measures of numerical understanding.

Overall, although most of these methods work well for older children, we found that they just don’t translate to two-year-olds. Their motor skills, attention span, and language abilities are still developing – and that affects how they perform on tasks, regardless of their actual mathematical thinking.

Conclusion: We Need Better Tools

Our review makes one thing clear: there are limited tools available for measuring mathematical skills in toddlers. Current tasks may either oversimplify and miss what’s happening, or they demand too much and misrepresent children’s abilities. If we want to truly understand how mathematical thinking begins, we need tools designed for toddlers, not adapted from other age groups.

Our current work aims to address this gap, we have developed new interactive activities to assess children’s early conceptions of number and are using these in studies with two-year-olds.

Three Key Takeaways

1. Task Failure Isn’t Always a Skill Failure

A toddler who fails to pick the larger dot array in a non-symbolic task (Bullet point 1 above) might not misunderstand quantity – they might just not know the word “more.” Separating performance issues from true conceptual gaps is essential.

So, failure at a task doesn’t always mean failure of understanding – it might just be a failure of communication or attention.

2. We Must Design Toddler-Friendly Tasks

Too many tasks assume attention spans or verbal comprehension beyond what’s realistic for two-year-olds. More reliable insights might be offered by new approaches which are play-based, interactive and use engaging methods.

We shouldn’t just scale down tasks from older age groups – we need to reimagine them entirely for toddlers.

3. Early Measurement Matters for Early Support

If we can better identify emerging numerical understanding at age two, we could better support children before they fall behind. That means earlier intervention, better learning environments, and more equitable outcomes in the long-term.

Disclaimer: A ChatGPT model was used to support the writing of this blogpost. For more information, contact b.woollacott@lboro.ac.uk

Centre for Mathematical Cognition

We write mostly about mathematics education, numerical cognition and general academic life. Our centre’s research is wide-ranging, so there is something for everyone: teachers, researchers and general interest. This blog is managed by Dr Bethany Woollacott, a research associate at the CMC, who edits and typesets all posts. Please email b.woollacott@lboro.ac.uk if you have any feedback or if you would like information about being a guest contributor. We hope you enjoy our blog!

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