Know if the product is not correct. Pupils learn a quick check to see if a product is incorrect. The video uses the value of the units to check solutions to multi-digit multiplication problems. Two short worksheets allow learners to practice using the method.

Concepts

multiplication, estimation multiplication, multiplication whole numbers, 2-digit multiplication

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Additional Tags

math

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Instructional Ideas

• Lead a discussion on why this method does not guarantee a correct answer
• Provide other methods for individuals to check solutions, such as digit sums

Classroom Considerations

• Assumes the class is familiar with multiplying multi-digit numbers

Pros

• Includes an answer key for faster grading
• Worksheets provide space to answer all questions and does not require extra paper

Cons

• None

Common Core

SL.4.2 SL.5.2 MP6 MP7 4.NBT.B.5 5.NBT.B.5