Summary
In this episode of Chalk Dust, Rebecca Birch and Nathaniel Swain are joined by Kris Boulton, founder and CEO of Unstoppable Learning, to explore atomisation, an approach to instructional design that breaks complex learning into carefully sequenced, manageable elements. Drawing on classroom footage of Kris teaching algebra to primary and secondary students at Mastery Schools Australia, the discussion examines how precise explanations, minimally different examples and systematic checking for understanding can enable students to master mathematical concepts that initially appear well beyond their capabilities.
Kris demonstrates how deliberate instructional design can remove unnecessary cognitive demands, allowing students to concentrate on exactly what they are learning. Through examples of expanding algebraic expressions, he explains why the selection and sequencing of examples matter, how to separate arithmetic from new mathematical procedures, and how mini whiteboards and immediate corrective feedback help teachers identify and address errors before moving forward. Central to his approach is the Penny Promise: if students give their attention and follow the instruction, the responsibility for their success rests with the teacher.
Throughout the episode, Rebecca, Nathaniel and Kris explore the relationship between instructional design, cognitive load, student motivation and teaching expertise. The conversation extends beyond mathematics into broader questions about teaching sentence construction, selecting examples, managing instructional pace and the balance between explicit modelling and guided practice. Ultimately, the episode challenges teachers to consider how much more students might learn when every explanation, example and practice opportunity is designed with precision.
Mentioned resources and explainers
Kris Boulton
Kris Boulton is an international teacher educator and education writer specialising in evidence-informed instructional design. He has contributed to England’s Early Career Framework and Ofsted’s Mathematics Inspection Framework, led teacher educator development at Teach First, and helped design Up Learn’s learning system.
Unstoppable Learning
Founded by Kris Boulton, Unstoppable Learning works with schools to improve mathematics instruction through a structured approach to instructional design known as atomisation. The organisation focuses on making complex learning accessible through precise explanations and carefully sequenced examples.
Atomisation
An approach to instructional design that breaks learning into a small number of fundamental elements, each requiring a particular form of explanation and sequencing. Kris argues that identifying these elements allows teachers to design instruction that minimises ambiguity and prevents predictable misconceptions.
The Penny Promise
Named after Kris’s early-career mentor, Penny Jones, the Penny Promise is a commitment to students that if they pay attention and follow the instruction, they will succeed. It places responsibility on the teacher to design and deliver instruction that makes success possible.
Engelmann and Carnine – Theory of Instruction
Siegfried Engelmann and Douglas Carnine developed Direct Instruction, a systematic approach to instructional design that informs Kris’s work. Their Theory of Instruction examines how examples, non-examples, transformations and carefully controlled variations can support accurate learning and generalisation.
Minimally Different Examples
Examples that change only one carefully selected feature at a time. By controlling what changes and what stays the same, teachers can direct students’ attention to the specific concept or procedure being taught.
The Setup Principle
A principle associated with Engelmann and Carnine’s instructional design in which irrelevant features of examples are kept constant while the feature being taught is varied. Kris discusses how this might apply to teaching sentence syntax without simultaneously introducing challenging vocabulary.
Cognitive Load and Instructional Design
Kris explains how unnecessary arithmetic can interfere with learning a new mathematical procedure. By using simple number facts or stopping tasks before the calculation stage, teachers can direct students’ attention towards the intended learning rather than competing demands.
Instruction and Testing Sequences
Kris distinguishes between the initial presentation of carefully sequenced examples and the subsequent testing sequence, where students respond independently on mini whiteboards. Teachers use these responses to identify errors, provide feedback and determine whether students are ready to progress.
Mini Whiteboards and Corrective Feedback
Mini whiteboards allow teachers to check every student’s response and provide immediate feedback. Kris demonstrates how repeated opportunities to respond, combined with precise correction, help students move towards mastery.
Kick-Yourself Mistakes
A term Kris credits to his mentor Penny Jones, describing small errors that students recognise immediately when shown the correct response. The approach helps normalise mistakes while encouraging students to attend carefully to the correction.
Instructional Pace
Kris discusses the importance of moving through examples and practice opportunities efficiently without sacrificing understanding. The principle of going as fast as you can, but as slow as you must captures the balance between providing sufficient scaffolding and maximising opportunities to practise.
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Takeaways
Atomisation breaks complex learning into fundamental elements that can be taught through carefully designed instructional sequences.
Precise instructional design can prevent misconceptions rather than simply responding to them after they occur.
The Penny Promise places responsibility for student success on the teacher, provided students attend to and follow the instruction.
Minimally different examples help students identify what changes and what remains constant, supporting generalisation.
Introducing one new element at a time reduces unnecessary cognitive demands and allows students to focus on the intended learning.
Teaching a new mathematical procedure does not necessarily require students to practise difficult arithmetic at the same time.
Students may need several closely sequenced practice opportunities before they can consistently apply a new procedure.
Atomisation may have applications beyond mathematics, including teaching sentence syntax and other aspects of writing.
Instructional pace matters because efficient routines create more opportunities for students to practise within the available learning time.
Effective teaching requires both subject expertise and the ability to transform that knowledge into explanations and examples that novices can understand.
Student success can be a powerful source of motivation, particularly when learners recognise that they have mastered something previously considered difficult.
Keywords
Kris Boulton, Unstoppable Learning, atomisation, instructional design, explicit instruction, mathematics teaching, algebra, minimally different examples, Engelmann and Carnine, Theory of Instruction, Penny Promise, cognitive load, worked examples, guided practice, mini whiteboards, corrective feedback, checking for understanding, instructional sequencing, generalisation, mathematical notation, instructional pace, mastery learning, student motivation, evidence-informed teaching, Chalk Dust podcast
