Investigate the claim that 999997=-3. Learners discover how to subtract large numbers using a quick method of addition. The video provides examples and shows how adding machines and computers apply this approach to subtraction.

Concepts

addition, subtraction, binary code

Show More Show Less

Additional Tags

science

Show More Show Less

Instructional Ideas

• Use board work to practice the subtraction by addition method
• Have pupils race to complete a problem with the traditional algorithm versus the subtraction by addition method

Classroom Considerations

• Expects a proficiency with the standard subtraction algorithm

• This video is hosted on YouTube

Pros

• Provides several examples
• Connects the method to a real-life application

Cons

• None