Students will understand that the standard algorithm for multiplication works whether the multiplication situation is iterating groups or comparing quantities. They will also understand that division can be related to the area models and arrays used for multiplication. This unit develops students’ skills with using the standard algorithm for multiplication and reinforces the inverse relationship between division and multiplication.
Key Concepts:
- Place value concepts and properties of operations are the foundation for the standard multiplication algorithm.
- The standard algorithm for multiplication works whether the multiplication situation is iterating groups or as comparison.
- We can relate the dividend, divisor, and quotient in a division problem to parts of an array model.
- We can relate the dividend, divisor, and quotient in a division problem to parts of an area model.
- We can use strategies based on place value, operations, and the relationship between multiplication and division.
Prior Knowledge Needed:
- Using area models and arrays for multiplication; (Grade 4 Unit 2; 4.NBT.B.5)
- Decomposing numbers to find a product; (Grade 4 Unit 2; 4.NBT.B.5)
- Strategies for division; (Grade 4 Unit 2; 4.NBT.B.6)
- Division-related vocabulary: divisor, dividend, quotient; (Grade 4 Unit 2; 4.NBT.B.5)
Units on the Horizon:
- Performing Operations with Decimals (Grade 5, Unit 10)
- Finalizing Multiplication and Division with Whole Numbers (Grade 5, Unit 15)
Lessons
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Lesson objective: Understand that the partial product method is a vertical representation of the calculations illustrated in the area model for multiplication. Students bring prior knowledge of using the area model to solve multi-digit multiplication pr...
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Lesson objective: Extend the understanding that the standard algorithm for multiplication is an efficient method for solving multi-digit multiplication problems. Students bring prior knowledge of multiplying multi-digit numbers using the partial product...
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Lesson objective: Multiply multi-digit numbers using the standard algorithm. This lesson helps to build procedural skill with multiplying multi-digit numbers. The standard algorithm is used here because supports fluency. This work develops students' und...
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Lesson objective: Solve problems to determine the area of a square or rectangle using multiplication. This lesson provides an opportunity for students to apply their knowledge and understanding of multiplication to a real-life situation. Students are as...
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Lesson objective: Understand that the standard algorithm for multiplication is a valid method for solving both iterating groups and comparison problems. Students bring prior knowledge of the standard algorithm for multiplication from 5.NBT.B.5. This pri...
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Lesson objective: Solve problems involving repeated equal groups and/or problems involving comparisons using the standard algorithm for multiplication. This lesson helps to build procedural skill with multi-digit multiplication. The standard algorithm i...
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Lesson objective: Solve multiplication problems involving iterating groups and comparisons. This lesson provides an opportunity for students to apply their knowledge and understanding of the standard algorithm for multiplication to a real-life situation...
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Lesson objective: Understand that the array model for multiplication can be used to find a dividend, divisor, or quotient in a division problem. Students bring prior knowledge of the array model for multiplication from 4.NBT.B.5. This prior knowledge is...
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Lesson objective: Solve division problems using multiplication arrays. This lesson helps to build procedural skill with division. Arrays are used because they support the idea that there is an inverse relationship between multiplication and division. Th...
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Lesson objective: Solve problems involving multiplication and division to plan three possible menus for a school picnic. This lesson provides an opportunity for students to apply their knowledge and understanding of the standard algorithm for multiplica...
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Lesson objective: Understand that the dividend, divisor, and quotient can be applied to an area model. Students bring prior knowledge of area models as a useful way to solve multiplication problems (4.NBT.B.5), and that when multiplying, factors go on t...
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Lesson objective: Use an area model to divide whole number dividends by a two-digit divisor. This lesson helps to build the procedural skill of dividing whole numbers with a two-digit divisor using an area model. An area model is used here because it co...
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Lesson objective: Understand that a variety of strategies and operations can be used to solve real-world problems. Students bring prior knowledge of how the standard algorithm can be used to efficiently multiply (5.NBT.B.5). This prior knowledge is exte...
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Lesson objective: Divide whole numbers by a two-digit divisor using partial quotients. This lesson helps to build the procedural skill of dividing whole numbers. Partial quotients is used here because it extends student work with area models and arrays,...
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Lesson objective: Solve multistep problems using a variety of strategies and operations. This lesson provides an opportunity for students to apply their knowledge and understanding of multiplication and division to a real-life situation. Students are as...
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