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5-Minute Check
• Tell whether each equation is balanced.
• 1) 1 dime x 3 = ( 1 dime + 1 nickel) x 3
• 2) 2 x 6 / 3 = 16 /4
• Complete the equation to make it balanced.
• 3) 3 x (8 x 5) / 4 = 2 x (m – 3)
Multiples of 10, 100, and 1,000
Objective
By the end of the lesson, you will be able to multiply multiples of 10, 100, and 1,000 using basic facts and patterns.
Standard 4NS3.2 - Demonstrate an understanding of, and the ability to use, standard algorithms for multiplying a multidigit number by a two-digit number and for dividing a multidigit number by a one-digit number; use relationships between them to simplify computations and to check results.
Introduce
• Let’s look at some math facts.
• 2 x 4 = 8
• 2 x 40 = 80
• 2 x 400 = 800
• And how about another?
• 3 x 6 = 18
• 3 x 60 = 180
• 3 x 600 = 1,800
• What pattern do you see?
Teach• Let’s try one together.
• 4 x 5 = ??
• 4 x 50 = ??
• 4 x 500 = ??
• What are the products of each number sentence?
• Looking at this pattern, do you notice anything?
Example
• The whale shark is the world’s largest fish. Its mouth is 5-feet long and each foot contains 600 teeth. How many teeth does a whale shark have?
• You can use basic facts and number patterns to multiply and solve.
• You need to find 5 x 600. Use the basic fact and pattern.
• 5 x 6 = 30
• 5 x 60 = 300
• 5 x 600 = 3,000 So, the whale shark has 3,000 teeth.
More Examples
Find 3 x 7,000.
3 x 7 = 21
3 x 70 = 210
3 x 700 = 2,100
3 x 7,000 = 21,000
So, 3 x 7,000 is 21,000. Notice that this answer is 3 x 7 with three zeros at the end.
Let’s hear from Mrs. Verughese!! Mrs. Verughese!!
Chance Tickets• Multiply. Use basic facts
and patterns.
• 2 x 1
• 2 x 10
• 2 x 100
• 2 x 1,000
• 6 x 8
• 6 x 80
• 6 x 800
• 6 x 8,000
• 7 x 9
• 7 x 90
• 7x 900
• 7 x 9,000
• Multiply. Use mental math.
• 3 x 20
• 8 x 600
• 9 x 9,000
• 7 x 7,000
Assignment
Page 265
•Red - 9-11, 15-17, 21, 23, 25-26
•Green - 9-11, 15-26, 28
•Purple – 9-27 odd, 28-29
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