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Wednesday, October 31, 2012

Multiplication With Arrays

                      Multiplication With Arrays

1.
array
2  in each row multiplied by 3 rows     2 x 3 = 6
in each column multiplied by 2 columns     3 x 2 = 6 

2.
array
7 in each row multiplied by 3 rows   7 x 3 = 21
3 in each column multiplied by 7 columns    3 x 7 = 21   

3.
array
6 in each row multiplied by 2 rows     6 x 2 = 12 
 2 in each column multiplied by 6 columns     2 x 6 = 12    

4.
array
 5 in each row multiplied by 4 rows     x 4 = 20
 4 in each column multiplied by 5 columns     4 x 5 = 20

5.
array
4 in each row multiplied by 5 rows    4 x 5 = 20
 in each column multiplied by 4 columns    5 x 4 = 20 


6.
array
4 in each row multiplied by 3 rows    4 x 3 = 12
3 in each column multiplied by 4 columns    3 x 4 = 12

7.
array
8 in each row multiplied by 6 rows     8 x 6 = 48
6 in each column multiplied by 8 columns    6 x 8 = 48

8.
array
7 in each row multiplied by 6 rows    7 x 6 = 42
6 in each column multiplied by 7 columns      6 x 7 = 42

9.
array
3 in each row multiplied by 5 rows     3 x 5 = 15
5 in each column multiplied by 3 columns     5 x 3 = 15

10.
array
3 in each row multiplied by 6 rows     3 x 6 = 18
 6 in each column multiplied by 3 columns     6 x 3 = 18



















Tuesday, October 30, 2012

Repeated Addition - On a Number Line


Multiplying on a number line


Five jumps, each is two steps. 5 × 2 = 10.

Example problems

1.  Write the multiplication sentence that the jumps on number line illustrate.
  
  


2.  Continue and draw jumps to fit the multiplication problem.

6 × 4 = 

 5 × 5 = 
 

3 × 10 =


Find 4 × 3 by skip-counting


Take four 'skips'.  Add three each time.  Notice where you land when 'skipping':
 
You landed at 3, 6, 9, 12.   4 × 3 = 12.
 
3.  Add repeatedly (or skip-count) to multiply.  You can use the number line to help.
3 × 2 =
6 × 3 =
4 × 5 =
3 × 10 =
2 × 11 =
3 × 7 =

4.  Fill in the multiplication table of 2!
1 × 2 =
2 × 2 =
3 × 2 =
4 × 2 =
5 × 2 =
6 × 2 =
7 × 2 =
8 × 2 =
9 × 2 =
10 × 2 =
11 × 2 =
12 × 2 =

Monday, October 29, 2012

Repeated Addition (2)

Multiplication as repeated addition

REMEMBER : 
5 + 5 + 5 = 3 x 5 = 15

Example : 

1.   2 + 2 + 2                     = 2 x 3 = 6

2.   5 + 5                           = 5 x 2 = 10

3.   1 + 1 + 1 + 1 + 1 + 1  = 1 x 6 = 6 

4.   3 lots of 10                = 10 x 3 = 30

5.   10 lots of 5                = 5 x 10 = 50

6.   7 lots of 2                  = 2 x 7 = 14

7.   3 + 3 + 3 + 3 + 3        = 5 lots of 3 = 15

8.   2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 = 8 lots of 2 = 16

9.   4 lots of 10                = 4 x 10 = 40

10.   6 lots of 2                =  6 x 2 = 12


Sunday, October 28, 2012

Repeated Addition - With Object (1)

      Multiplication as Repeated Addition

1.

Repeated Addition
 Repeated Addition: 7 + 7 + 7 + 7 + 7 + 7
                         so
                        7 x 6 = 42                                                                                  

2.

Repeated Addition
 Repeated Addition: 5 + 5 + 5 + 5 = 20
                        so
                        5 x 4 = 20
  

3.


Repeated Addition
 Repeated Addition: 10 + 10 + 10 = 30
                             so
                          10 x 3 = 30

4.

Repeated Addition
 Repeated Addition: 8 + 8 + 8 + 8 = 32
                        so
                       8 x 4 = 32



5.

Repeated Addition
 Repeated Addition: 3 + 3 + 3 + 3 = 12
                          so 
                         3 x 4 = 12

6.

Repeated Addition
 Repeated Addition: 6 + 6 + 6 + 6 = 24
                          so
                         6 x 4 = 24
      

7.

Repeated Addition
 Repeated Addition: 2 + 2 + 2 = 6
                         so
                         2 x 3 = 6 


   

8.

Repeated Addition: 4 + 4 + 4 + 4 = 16
                         so
                        4 x 4 = 16

9.


Repeated Addition: 2 + 2 + 2 = 6
                         so
                        2 x 3 = 6

10.

Repeated Addition: 4 + 4 = 8
                          so
                       4 x 2 = 8

Saturday, October 27, 2012

Maths vocabulary: Year 2 multiplication and division


Maths vocabulary: Year 2 multiplication and division

It is in year 2 that multiplication and division really become
important. Understanding terms such as ‘lots of’, ‘share equally’ and
‘divide’ are all introduced in a practical sense i.e. children need
plenty of opportunities to share items out and to group into sets.
The vocabulary introduced in year 2 concerning multiplication and
division of numbers includes:
lots of           groups of
times            multiply          multiplied by      multiple of

once             twice               three times
four times   five times       up to ten times  
times as (long, big etc)
repeated addition
array             row              column
share equally     one each    two each   three each    etc
group in pairs        group in tens
equal groups of
divide          divided by               divided into


*Remember that new vocabulary should not be introduced in
isolation, but in suitable contexts.


Thursday, October 25, 2012

Factors and Products

Factors and ProductsLesson

Factors and Products      
An array is data arranged in rows or columns. They can be used to represent factors. You can use chips, cubes, blocks, etc. to make an array. Stars are used in the example below to represent the factors and product for the number 12.
Number 12
************1 by 12
******
******
2 by 6
****
****
****
3 by 4
Consider the following pairs of arrays the same:
 1 by 12 and 12 by 12 by 6 and 6 by 23 by 4 and 4 by 3.Therefore, the number 12 has 3 different arrays.
The factors of 12 are 1, 2, 3, 4, 6, and 12.
The array represents the product.

Number line
You can skip count using a number line to find the product.
3 x 4 = 12
Read: 3 times 4 equal to 12.

The numbers 3 and 4 are the factors and the number 12 is the product.
 
Example:
The model below is an array that represents
 2 x 4 = 8
There are 2 rows and 4 columns.
The factors are 2 and 4.The product is 8.
The number line below also represents the multiplication sentence 2 x 4 = 8.

Remember: If each array represents a product, look at the sides of the arrays, and you will get all the factors for that number.