Arrays and Using an Expanded Algorithm Literature Link: The Grapes of Math by Greg Tang (1-2 pages) Lesson 6-1 CCSS 4.NBT.5

MATH Essential Questions How do I know which computational method (mental math, estimation, paper and pencil, and calculator) to use? MATH Essential Questions

MATH Essential Questions How do mathematical operations relate to each other? MATH Essential Questions

MATH Essential Questions Why do I need mathematical operations? MATH Essential Questions

Warm Up 4 X 8 9 X 7 5 X 5 3 X 6 8 X 6 7 X 7

Today’s Lesson In this lesson, you will learn an algorithm to help you record the partial products as you multiply. Let’s look at the Envision Video for this lesson and take the quiz.

Think and Write We use arrays to solve multiplication problems by representing the problem as a number of rows with equal objects in each row. In real life what can you think of that comes in rows? Picture albums, desks in a classroom, chairs in an auditorium, plane seats, etc.

Arrays Array: A strategy used to solve a multiplication problem by drawing equal rows with an equal number of objects in each row. (Enter this definition in your Interactive Math Notebook) Example: For the problem 2 x 4, you would make 2 rows with 4 objects in each row.

Partial Products with Arrays How can you make an array to show 4 X 12? Look at the tens and ones in the 12 as two different numbers. Make an array for 4 X 1, and another for 4 X 2. Remember that since the 1 is in the tens place, and 4 X 1 = 4, it is really worth 40. 4 X 2 = 8 Now add 40 + 8.

Problem 1 Matt arranges his video games in 4 rows with 16 games in each row. Build an array to show Matt’s games.

Problem 2 Abby bakes 3 rows of cupcakes with 14 cupcakes in a row. Build an array to find out how many cupcakes Abby baked.

Problem 3 Tyler puts his baseball cards in 4 rows with 26 cards per row. Build an array to find how many cards Tyler has in all.

Problem 4 Gavin puts his dinosaurs into 3 rows with 22 dinosaurs in each row. Build an array to see how Gavin arranged his dinosaurs and find his total number of dinosaurs.

Problem 5 Kara bakes cookies in 6 rows with 16 cookies per row. Build an array to find out how many cookies Kara baked in all.

Challenge How many more stamps are in 4 rows of rocket stamps than 5 rows of flower stamps? Type of Stamps Number Per Row Rocket 30 Presidents 24 Flower 22

Lesson Wrap Up In this lesson, you recorded multiplication after finding partial products using an expanded algorithm. Reflection in Notebook: At the end of this unit, I want to be able to...  Center Activity – Toss and Talk (6-1). Homework (6-1 Practice) for one “Paw Signature” and (6-1 Reaching & Practice) if you want two “Paw Signatures.” Website for Practice: Website for Practice: http://www.mathplayground.com/multiplication01.html