CONFIDENTIAL1 Today we will discuss about the topic: Multiply 2-4 digit by 1 digit Good Afternoon! Let’s Warm up:. 1) 3 x 4 =2) 12 x 3 = 5) Find out the value of 2x2 with the help of the model given below? 3) 5 x 5 =4) 6 x 6 =

CONFIDENTIAL2 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.

CONFIDENTIAL3 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. REVIEW

CONFIDENTIAL4 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 = = 21 Double a Known Fact Find 8 x 6. 8 x 6 = (4 x 6 ) + (4 x 6) = = 48 8 groups of 6 = 4 groups of groups of 6 REVIEW

CONFIDENTIAL5 We looked into the Multiplication Table and its patterns : x In the table, the pattern of the square numbers are shown within the yellow squares.

CONFIDENTIAL6 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

CONFIDENTIAL7 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

CONFIDENTIAL8 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.

CONFIDENTIAL9 You can use pattern of factors and products to multiply mentally. 3 x 2 = 6 3 x 20 = 60 3 x 200 = x 2,000 = 6,000 Multiply: 4 x 3 x 7

CONFIDENTIAL10 We multiply numbers by first lining up the digits in the following manner: Find: 236 x X 6 First multiply 6 with 6 to obtain STEP 1: Regroup 36 as 3 tens and 6 ones.

CONFIDENTIAL X 6 Again, multiply 6 with 3 at the tens place to obtain 18. Then, add 3 and 18 to obtain STEP 2: Regroup 21 as 2 hundreds and 1 tens.

CONFIDENTIAL X 6 Then, multiply 6 with 2 at the hundreds place to obtain 12. Then, 2 and 12 to obtain STEP 3: Hence, the result. Multiply: 564 x 3

CONFIDENTIAL13 Estimating Products: Estimate 6 x 44.  By Estimate, we mean an answer that is close to the exact answer. While estimating products, we round the greater factor. 6 x x 40 =240 Round to the nearest tens. Hence, the estimated value of 6 x 44 is 240.

CONFIDENTIAL14 There are two terms related to Estimation.  Overestimate: It is an estimate greater than the exact answer.  Underestimate: It is an estimate less than the exact answer. Example:Estimate: 5 x 36 5 x 36 = x 40 = > 180 Round 36. Example:Estimate: 5 x 33 5 x 33 = x 30 = < 165 Round 33.

CONFIDENTIAL15 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, Here, we see that the greater factor is converted to the Expanded Form.

CONFIDENTIAL16 Then multiply each part by 5: 5 x 3,000 =15,000 5 x 800 = 4,000 5 x 30 = x 9 = 45 Then finally add each part: 15, , = 19,195 Hence, 5 x 3,839 = 19,195.

CONFIDENTIAL17 BREAK

CONFIDENTIAL18 GAME Click on the link below for some exciting puzzle puzzles/12-piece-jigsaw/050205food.html

CONFIDENTIAL19 Assignments Using the Associative Property of Multiplication, find the products of the following. 1) (3 x 5) x 7 = 4) (6 x 5) x 2 = 2) (8 x 2) x 6 = 3) (4 x 7) x 4 =

CONFIDENTIAL20 Find the product: 573 X X 7 5)6)

CONFIDENTIAL21 Estimate the products of the given problems: 7) 6 x 44 8) 7 x 48

CONFIDENTIAL22 Multiply using the Distributive Property : 9) 6 x 69410) 2 x 7,295

CONFIDENTIAL23 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 Very Good! Let's Review You can use pattern of factors and products to multiply mentally. 3 x 2 = 6 3 x 20 = 60 3 x 200 = x 2,000 = 6,000

CONFIDENTIAL24 We multiply numbers by first lining up the digits. 236 X 6 First multiply 6 with 6 to obtain STEP 1: Regroup 36 as 3 tens and 6 ones. 236 X 6 Again, multiply 6 with 3 at the tens place to obtain 18. Then, add 3 and 18 to obtain STEP 2: Regroup 21 as 2 hundreds and 1 tens.

CONFIDENTIAL X 6 Then, multiply 6 with 2 at the hundreds place to obtain 12. Then, 2 and 12 to obtain STEP 3: Hence, the result. Estimate 6 x 44.  By Estimate, we mean an answer that is close to the exact answer. While estimating products, we round the greater factor. 6 x x 40 =240 Round to the nearest tens.

CONFIDENTIAL26  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. Split 3,839 into 4 parts: 3, x 3,000 =15,000 5 x 800 = 4,000 5 x 30 = x 9 = 45 Then finally add each part: 15, , = 19,195 Multiply: 5 x 3,839 Then multiply each part by 5:

CONFIDENTIAL27 You have done a nice job. See you in the next session.