The Year 4 Subtract Two 4-Digit Numbers – More than One Exchange PowerPoint guides both teachers and children through the lesson, including use of the varied fluency, reasoning and problem solving, deeper reasoning and scaffolded resources. Key learning information about this step:
Key Vocabulary
exchange: When a digit is taken from one place value column and placed in another.
formal written method: This is also known as the column method for addition, subtraction and multiplication. For division, this may also be known as the bus stop method.
place value chart: Used to identify the value of the digits that make up a number.
placeholder: 0 is used to hold a place in a number and maintain its place value.
Varied Fluency
Knowledge Organiser
• Designed to support all children via key information and examples.
Scaffolded Examples
• Completing three column subtractions with more than one exchange by following four given steps and writing the exchanges; comparing answers using <, > or = .
Support
• Q1: Compare two subtractions using <, > or =; both need two exchanges and the digits and exchanges are written in the grids.
• Q2: Match two subtractions to their answers; the digits are written in the grids.
• Q3: Find one missing digit in each subtraction; the answer is given.
Core
• Q1: Compare two subtractions using <, > or =; the digits are written in the grids.
• Q2: Match two subtractions to their answers; zero as a placeholder.
• Q3: Find two missing digits using the inverse; one has a 3-digit number.
Stretch
• Q1: Line up the digits yourself, then compare the answers of subtractions.
• Q2: Line up the digits yourself; match two subtractions with a two-part exchange.
• Q3: Find a whole missing number in each subtraction using the inverse.
Reasoning and Problem Solving
Support
• Q1: Reasoning – Decide whether a statement is correct by finding the missing part of a bar model; the steps are spelled out.
• Q2: Reasoning - Judge a character’s claim about how many exchanges a subtraction needs.
• Q3: Problem Solving - Build three subtractions that each need exactly two exchanges.
Core
• Q1: Reasoning – Decide whether a statement is correct by finding the missing part of a bar model and comparing the parts.
• Q2: Reasoning - Judge a character’s claim about zero as a placeholder and the hundreds digit.
• Q3: Problem Solving - Build three subtractions whose answers all share a given thousands digit.
Stretch
• Q1: Reasoning - Find the missing part of a bar model, then compare the two parts; a two-part exchange is needed.
• Q2: Reasoning - Judge a character’s claim about exchanging across a column with nothing to give.
• Q3: Problem Solving - Build three pairs of numbers with a given difference that each need an exchange across at least one 0.
Deeper Reasoning
The questions in this set focus on problem solving with subtraction to deepen understanding in subtracting numbers with up to four digits with more than one exchange using the formal written methods of columnar subtraction where appropriate, and solving two-step subtraction problems in contexts, deciding which operations and methods to use and why.
