Mighty Multiplication and Dominant Division
MULTIPLY!
Did you happen to notice the banner in the heading?
If I just happened to want to know how many strips, or columns there were, I could count the number of strips (14) and multiply that number by 1 (because there is one set of columns) to discover how many strips or columns there are. 14x1= 14.
If for some quirky reason, I want to know how many sections there are in the whole heading, I would need to take the number of columns (14) and then count the number of pieces in one section (I counted 26.) I would then mulitply the columns by the number of sections in each column. 1 4 x 2 6 =
14 columns x 26 pieces
The above heading is a good model for 14x26.
So, what is 14x26?
I could solve this by using an area model.
I could also solve this by separating the numbers 14 and 26 into their place value.
2 6 = 20 + 6 and 1 4 = 10 + 4
What actually happens here is:
2 0 x 10 + 20 x 4 and 6 x 10 + 6 x 4
20 x 10= 200 + 20 x 4= 80 and 6 x 10= 60 + 6 x 4 = 24
200+80= 280 and 60 + 24 =84
add both products together : 280 + 84 = 364
So, 26 x 14 = 364
There are 364 sections in the banner heading above.
In fourth grade, students may use a standard algorithm to solve 26x 14
2 Can you see how breaking the numbers into place value works
2 6 to get the same answer to 26x14 as the standard algorithm?
x 1 4
-----------------
1 0 4 Here I showed 2 different methods.
+ 2 6 0 to solve the same problem 26x14
------------------- Math is so awesome.
3 6 4 There is more than one way to solve a problem!
This clip is a Multiplication Number Talk. It is excellent.
Triple Digit Multiplication grade 4, grade 5
There are 2 examples demonstrated in the video clip below.
Click on blue link below.
This example shows the area model, and the standard algorithm
to find the solution for:
3 5 2 x 4 8 1
(This is the entire address, you can cut and paste it into your browser.)
It is helpful to remember how to break the numbers apart into their place value.
352= 300+50+2 481= 400+80+1
Now can you visualize where you would draw in the lines to create an area model? Will you explain how to solve this problem?
400 80 1
300
50
2
Notice that this time I showed 352 as 300+50+2. In the area model in the video clip, 352 is written as 2+50+300.
This demonstrates thereof the distributive property.
What answer did you get? Is it the same as in the video clip?
Can you think of another way to solve 352x481?
grade 3
Things that come in groups-
repeated addition or multiplication ?
3+3+3=9 or, 3x3=9
The videoclip on the below left is a nice introduction to multiplication.
The videoclip below on the right helps to show how multiplication and division are connected.
When you multiply think: How many groups of how many things, or how many things are in how many groups. When we multiply, we find the total number, of groups, or things.
grades 3,4,5
Multiplication is finding the whole.
We take 2 parts and multiply to find the whole.
DIVISION is splitting things up!
Yes, when we divide, we are taking a whole, and splitting ~ or dividing that whole into groups.
8 divided by 2
I have 8 items as my whole. * * * * * * * *
I split them, or divide 8 into 2 groups. * * * * l * * * *
There are 4 items in each group * * * * * * * *
So, 8 divided by 2 equals 4
Below is a fun clip which helps to explain division. Enjoy! (Will you be dancing to the beat?) grade 4
grade 4,5
In Fairport, we begin with a division method using partial quotients to assist our students in understanding the operation in terms of place value. Watch the video clip below as another demonstration.
Math is math, this is simply a different way to solve with an emphasis on place value understanding.
grade (4)5
The above example shows another way to divide. This is called long division.
*~~~~~~~~~*~~~~~~~~~*~~~~~~~~~*~~~~~~~~~*
grade 5
Whoa! This is long division with BIG numbers.
Chill out kids. The process is the same as the example above.
There are just few more numbers! Breathe, you got this!
