The Year 6 Find Missing Numbers 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
inverse operations: Used to check working out or to find a starting number by using the opposite operation. Addition is the inverse of subtraction and vice versa. Multiplication is the inverse of division and vice versa.
bar models: Show how numbers can be split into different parts, by splitting them into bars or boxes. Bar models can be used to solve a wide variety of calculations, showing the relationship between the whole model and the parts.
estimate: To make a sensible guess at what the answer could be. You usually estimate the answer by rounding the numbers to make the calculation easier. Another word for estimate is approximate.
Varied Fluency
Knowledge Organiser
• Designed to support all children via key information and examples.
Scaffolded Examples
• Finding a missing part or whole with sentence stems; keeping a total the same.
Support
• Q1: Use a bar model to find a missing part or whole; no exchanging needed.
• Q2: Keep the total the same to find a missing number; change given.
• Q3: Keep the difference the same to find a missing number; change given.
Core
• Q1: Use a bar model to find a missing part or whole; exchanging is needed.
• Q2: Keep the total the same; one number changes to a multiple of 10 or 100.
• Q3: Keep the difference the same; one number changes to a multiple of 100.
Stretch
• Q1: Complete an empty bar model, then find the missing part; = can come first.
• Q2: Keep the total the same; work out a change not to a multiple of 10.
• Q3: Keep the difference the same; work out a change not to a multiple of 10.
Reasoning and Problem Solving
Support
• Q1: Reasoning – explain whether a character keeps the difference the same; the working is shown.
• Q2: Reasoning – explain whether two bar models have the same missing part; changes of 100 or 200; a hint is given.
• Q3: Problem Solving – find three possible missing parts for a bar model; the first step is given.
Core
• Q1: Reasoning – explain whether a character keeps the difference the same; one number changes to a multiple of 1,000.
• Q2: Reasoning – explain whether two bar models have the same missing part; changes of less than 100.
• Q3: Problem Solving – find three possible missing parts for a bar model within a range and a rule.
Stretch
• Q1: Reasoning – explain whether a character keeps the difference the same when numbers decrease or the missing number is subtracted.
• Q2: Reasoning – judge a reason given for two bar models having the same missing part.
• Q3: Problem Solving – find three possible pairs of equal missing parts for a bar model with three parts.
Deeper Reasoning
The question in this set focuses on problem solving with addition and subtraction to deepen understanding in adding and subtracting numbers mentally with increasingly large numbers, and solving addition and subtraction multi-step problems in contexts, deciding which operations and methods to use and why.
