HBS Math Support

Whole Number Multiplication

Videos

Place value when multiplying or dividing by 10 -Khan Academy
Dividing whole numbers by 10 – Khan Academy
Box Method 3x1 - Math with Mr. J
Multiply 3 digit numbers by 1 digit using area models – LearnZillion
Box Method 2x2 - Math with Mr. J
2×2 Digit Multiplication – Mashup
Turtlehead Multiplication Method – factivation.com
Box Method – Doceri
Box Method – Math with Mr. J
Grid Method – Geekie Teachie
Partial Quotient – Mr. Epp
Area model to multiply – PBS
2×2 digit multiplication using Partial Products – PBS

Place value when multiplying and dividing by 10 (video) | Khan AcademyLindsay discusses how multiplying and dividing by 10 affects place value.

Dividing whole numbers by 10 (video) | Khan AcademyLindsay finds a pattern from dividing whole numbers by 10.

Area Model | PBS LearningMediaWhen first learning to multiply two two-digit numbers your child will use the area model.To start, your child will use her knowledge of place value to decompose into tens and ones. To decompose means to break apart. Let’s decompose these numbers by the value of each digit.The value of two tens is twenty. The value of three ones is three. Three tens is thirty. And five ones is five. Decomposing numbers allows your child to use the multiplication fluency she developed in third grade to multiply large numbers with mental math.So, what is twenty-three times thirty-five?Three tens times two tens equals sixty tens or six-hundred. Thirty tens times three equals nine tens or ninty. Twenty tens times five equals ten tens or one-hundred. And three times five equals fifteen. Your child will then add these products together. Six-hundred plus ninety equals six-hundred ninety. One-hundred plus fifteen equal one-hundred fifteen. By fourth grade, your child will fluently add three-digit numbers, like this, using the standard algorithm.Your child can clearly see why twenty-three times thirty-five equals eight-hundred-five. The area model gives your child a visual representation that decomposes the numbers she is multiplying. At this point in fourth grade, your child is developing a pictorial level of understanding, which will give her a strong foundation for using partial products and, later, using the standard algorithm to multiply.

Area Model Multiplication Video | Multiplying Partial Products SongWatch as Farmer Maslow takes us on a tour of his farm. He needs to know Area Model Multiplication to know how many seeds to plant.

Partial Products | PBS LearningMediaWhen your child first learns to multiply two two-digit numbers, she will use the area model. This visual tool illustrates how to decompose numbers and find four different products. As her skills improve, she will move from this pictorial model into a concrete method called partial products. Using partial products to solve forty-three times fifty-six, looks like this. She will start by multiplying tens times tens. Next, she will multiply tens times ones. Then, ones times tens and last, ones times ones.These are called partial products. This is the product, or answer. Using partial products removes the pictorial step but places the same emphasis on the actual value of the numbers being multiplied.By the end of fourth grade, your child will use the standard algorithm to multiply! This algorithm is used to develop an abstract level of understanding. If she jumps right to using the algorithm, she will not develop the conceptual understanding of multiplying two-digit numbers. The standard algorithm has fewer lines of work because your child has a greater understanding of what she’s multiplying! Your child knows the actual value of these products because she has a strong understanding of partial products.And that’s good to know.

Virtual Manipulatives

Area Model – Math Learning Center
Place Value Disks – Didax
Area Model Multiplication – Phet

‪Area Model Multiplication‬

Practice

Online Game

Vocabulary

Product
Quotient
Remainder
Estimate

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