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Good Afternoon!. Today we will discuss about the topic: Multiply 2-4 digit by 1 digit. Let’s Warm up:. 1) 3 x 4 =. 2) 12 x 3 =. 3) 5 x 5 =. 4) 6 x 6 =. 5) Find out the value of 2x2 with the help of the model given below?. REVIEW. Let’s discuss what we did in the last session.
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Good Afternoon! Today we will discuss about the topic: Multiply 2-4 digit by 1 digit Let’s Warm up:. 1) 3 x 4 = 2) 12 x 3 = 3) 5 x 5 = 4) 6 x 6 = 5) Find out the value of 2x2 with the help of the model given below? CONFIDENTIAL
REVIEW Let’s discuss what we did in the last session. We learnt about the following terms: • Multiple: It is the product of a number and any whole number. • Even numbers: Whole numbers that are divisible by 2 are even numbers. • Odd numbers: Whole numbers that are not divisible by 2 are odd numbers. • Prime numbers: Numbers whose factors are only 1 and the number itself are prime numbers. • Composite numbers: All the non-prime numbers except 0 and 1, are Composite Numbers. CONFIDENTIAL
REVIEW We can multiply by the means of Skip Counting also. By Skip Counting we mean that we can find the multiples of any number by hopping equal steps on the number line. • Here the numbers are taking 3 jumps each of 2 steps. 2 2 2 0 1 2 3 4 5 6 CONFIDENTIAL
REVIEW There are other strategies that can be used for multiplication. Find 7 x 3. Use a Known Fact 7 groups of 3 = 7 groups of 2 plus 7 7 x 3 = 7 x 2 + 7 = 14 + 7 = 21 Find 8 x 6. Double a Known Fact 8 groups of 6 = 4 groups of 6 + 4 groups of 6 8 x 6 = (4 x 6 ) + (4 x 6) = 24 + 24 = 48 CONFIDENTIAL
We looked into the Multiplication Table and its patterns : In the table, the pattern of the square numbers are shown within the yellow squares. CONFIDENTIAL
Today we will learn to Multiply 2-4 digit by 1 digit Multiplication is an operation on two numbers to find a product. Like 3 x 4 = 12. ASSOCIATIVE PROPERTY: While multiplying, we can change the grouping of the factors and the product stays the same. EXAMPLE: 2 x (3 x 4) = (2 x 3) x 4 2 x (3 x 4) = 2 x 12 = 24 (2 x 3) x 4 = 6 x 4 =24 CONFIDENTIAL
Uses of the ASSOCIATIVE PROPERTY: Find: 2 x 6 x 4 Here, Associative Property of Multiplication can be used to multiply the three factors. We will see that the grouping of the numbers does not affects the answer. STEP 1: Use parentheses to show the grouping. 2 x 6 x 4 = (2 x 6) x 4 CONFIDENTIAL
STEP 2: Look for a known fact to multiply. 2 x 4 is a known fact. STEP 3: Use the Commutative Property to change the order, if necessary. (2 x 6) x 4 = 2 x (6 x 4) = 2 x 24 = 48 Therefore, the product of 2 x 6 x 4 is 48. CONFIDENTIAL
You can use pattern of factors and products to multiply mentally. 3 x 2 = 6 3 x 20 = 60 3 x 200 = 600 3 x 2,000 = 6,000 Multiply: 4 x 3 x 7 CONFIDENTIAL
Find: 236 x 6 We multiply numbers by first lining up the digits in the following manner: Regroup 36 as 3 tens and 6 ones. 3 236 X 6 STEP 1: 6 First multiply 6 with 6 to obtain 36. CONFIDENTIAL
STEP 2: Again, multiply 6 with 3 at the tens place to obtain 18. Then, add 3 and 18 to obtain 21. Regroup 21 as 2 hundreds and 1 tens. 23 236 X 6 16 CONFIDENTIAL
STEP 3: Then, multiply 6 with 2 at the hundreds place to obtain 12. Then, 2 and 12 to obtain 14. Hence, the result. 23 236 X 6 1416 Multiply: 564 x 3 CONFIDENTIAL
Estimating Products: • By Estimate, we mean an answer that is close to the exact answer. Estimate 6 x 44. While estimating products, we round the greater factor. 6 x 44. Round to the nearest tens. 6 x 40 =240 Hence, the estimated value of 6 x 44 is 240. CONFIDENTIAL
There are two terms related to Estimation. • Overestimate: It is an estimate greater than the exact answer. Round 36. Example: Estimate: 5 x 36 5 x 40 = 200 5 x 36 = 180 200 > 180 • Underestimate: It is an estimate less than the exact answer. Round 33. Example: Estimate: 5 x 33 5 x 30 = 150 5 x 33 = 165 150 < 165 CONFIDENTIAL
We can do multiplication by other methods also. Multiply: 5 x 3,839 Here we use the Distributive Property to multiply 5 x 3,839 Split 3,839 into 4 parts: 3,000 + 800 + 30 + 9 Here, we see that the greater factor is converted to the Expanded Form. CONFIDENTIAL
Then multiply each part by 5: 5 x 3,000 =15,000 5 x 800 = 4,000 5 x 30 = 150 5 x 9 = 45 Then finally add each part: 15,000 + 4,000 + 150 + 45 = 19,195 Hence, 5 x 3,839 = 19,195. CONFIDENTIAL
BREAK CONFIDENTIAL
GAME Click on the link below for some exciting puzzle http://www.thekidzpage.com/onlinejigsawpuzzles/jigsaw-puzzles/12-piece-jigsaw/050205food.html CONFIDENTIAL
Assignments Using the Associative Property of Multiplication, find the products of the following. 1) (3 x 5) x 7 = 2) (8 x 2) x 6 = 3) (4 x 7) x 4 = 4) (6 x 5) x 2 = CONFIDENTIAL
Find the product: 5) 6) 573 924 X 3 X 7 CONFIDENTIAL
Estimate the products of the given problems: 7) 6 x 44 8) 7 x 48 CONFIDENTIAL
Multiply using the Distributive Property : 9) 6 x 694 10) 2 x 7,295 CONFIDENTIAL
Very Good! Let's Review Multiplication is an operation on two numbers to find a product. Like 3 x 4 = 12. ASSOCIATIVE PROPERTY: While multiplying, we can change the grouping of the factors and the product stays the same. EXAMPLE: 2 x (3 x 4) = (2 x 3) x 4 You can use pattern of factors and products to multiply mentally. 3 x 2 = 6 3 x 20 = 60 3 x 200 = 600 3 x 2,000 = 6,000 CONFIDENTIAL
We multiply numbers by first lining up the digits. STEP 1: First multiply 6 with 6 to obtain 36. Regroup 36 as 3 tens and 6 ones. 3 236 X 6 6 STEP 2: Again, multiply 6 with 3 at the tens place to obtain 18. Then, add 3 and 18 to obtain 21. Regroup 21 as 2 hundreds and 1 tens. 23 236 X 6 16 CONFIDENTIAL
STEP 3: Then, multiply 6 with 2 at the hundreds place to obtain 12. Then, 2 and 12 to obtain 14. Hence, the result. 23 236 X 6 1416 • By Estimate, we mean an answer that is close to the exact answer. Estimate 6 x 44. While estimating products, we round the greater factor. Round to the nearest tens. 6 x 44. 6 x 40 =240 CONFIDENTIAL
Overestimate: It is estimate greater than the exact answer. • Underestimate: It is estimate less than the exact answer. We also use the Distributive Property to multiply. Multiply: 5 x 3,839 Split 3,839 into 4 parts: 3,000 + 800 + 30 + 9 Then multiply each part by 5: 5 x 3,000 =15,000 5 x 800 = 4,000 5 x 30 = 150 5 x 9 = 45 Then finally add each part: 15,000 + 4,000 + 150 + 45 = 19,195 CONFIDENTIAL
You have done a nice job. See you in the next session. CONFIDENTIAL