Learn Multiplication - Standard Method
-
Upload
mark-runge -
Category
Education
-
view
67 -
download
0
Transcript of Learn Multiplication - Standard Method
www.kidsalgebra.com
You need to check with your Teacher if they want
you to learn the “Standard” method of
multiplication or the “Lattice” method.
www.kidsalgebra.com
You’re free to check out both methods, but in this
lesson you’ll learn the “Standard” method of
multiplication.
1 2 3 4 5 6 7 8 9 10 11 122 4 6 8 10 12 14 16 18 20 22 243 6 9 12 15 18 21 24 27 30 33 364 8 12 16 20 24 28 32 36 40 44 485 10 15 20 25 30 35 40 45 50 55 606 12 18 24 30 36 42 48 54 60 66 727 14 21 28 35 42 49 56 63 70 77 848 16 24 32 40 48 56 64 72 80 88 969 18 27 36 45 54 63 72 81 90 99 10810 20 30 40 50 60 70 80 90 100 110 12011 22 33 44 55 66 77 88 99 110 121 13212 24 36 48 60 72 84 96 108 120 132 144
By now you should know all of your Times Tables.
So you’ll know answers like 3 x 8 = 24
without counting.
x
=
www.kidsalgebra.com
But you also need to know how to multiply numbers bigger than 12.
That’s because you need to be able to solve problems like this one …
Farmer Brown has 23 tomato gardens on his farm.
Each garden has 16 rows of 64 tomato plants.
How many tomato plants does Farmer Brown have?
www.kidsalgebra.com
To answer this question you need to know how to multiply numbers that
are bigger than 12. Like 16 x 64.
But the biggest single number you’ll ever need to multiply by is 9, so you really only need to remember up to
your 10 times tables.
That’s already made your job of learning multiplication a lot easier!
www.kidsalgebra.com
So here’s the problem that we’ll solve to show you how to do “Standard” multiplication.
Farmer Brown has 23 tomato gardens on his farm.
Each garden has 16 rows of 64 tomato plants.
How many tomato plants does Farmer Brown have?
www.kidsalgebra.com
www.kidsalgebra.com
To solve problems like this, you have to decide on two things:
(1) What Answer are you looking for.&
(2) What Steps do you need to take to find the Answer.
The Answer you want is:“How many tomato plants does
Farmer Brown have?”
Or more simply, the
“Total number of tomato plants.”
www.kidsalgebra.com
The 1st Step is to calculate how many Tomato plants there are in each
Garden. Each Garden has this many tomato
plants: 16 rows of 64 Tomato plants.
www.kidsalgebra.com
9 10 11 12 13 14 15 16
1 2 3 4 5 6 7 8
xx
xx
xx
xx
xx
xx
xx
xx
xxxx
xx
xx
xx
xx
xx
xx
xxxxxxxx
xxxxxxxx
xxxxxxxxxxxxxxxx58605957
6264636158605957
626463
61
16 rows
64 per rowThis is what each Tomato garden looks like
The 2nd Step is to calculate …How many tomato plants Farmer
Brown has in his 23 tomato gardens.
www.kidsalgebra.com
12345
678910
1112131415
1617181920
212223
This is what all of his 23 tomato gardens look like from high above.
You can draw a picture of the two Steps and the Answer like this:
www.kidsalgebra.com
1st Step 2nd Step Answer
So here are the two Steps to get to the Answer.
1st Step: Number of tomato plants in each Garden.
2nd Step: Number of tomato plants in all 23 Gardens.
www.kidsalgebra.com
1st Step:
16 x 64
2nd Step:Answer from Step 1 x 23
Answer: Total Plants
In the 1st step we multiply the16 rows by 64 Tomato plants in each
row.
You could write it down like this:16 x 64 =
But to multiply you must write it like this:
www.kidsalgebra.com
64x
16
www.kidsalgebra.com
Writing numbers in columns like this splits the “Singles” column to the right
from the “Tens” column to the left.When you have 10 “Singles” it
becomes a “Ten” and when you have 10 “Tens” it becomes a “Hundred”.This is just like using your 10 times
table.T S6 41 6
Singles Column.Tens Column.
www.kidsalgebra.com
Rule # 1: Always put the smallest number at the bottom.
16 x 64 =
6416
16 is smaller than 64.
www.kidsalgebra.com
Rule # 2: Make one calculation line for each of the digits in the bottom
line.Then add one more line for the
Answer.16 has 2 digits.
6416
12
1 2 One line for each of the 2
digits.
One line for the answer.
x
www.kidsalgebra.com
Rule # 3: Multiply each digit on thetop line by each digit on the bottom
line starting from the right.
64 The 4 is the “ones” digit in the top line and 6 is the “ones” digit in the bottom
line.
x 16
www.kidsalgebra.com
The 2 in the answer 24 is 2 “Tens”.So you must “Carry” the 2 to the
“Tens” column below the 1 in the 16 like this: 6 x 4 = 24
641642
x
www.kidsalgebra.com
641642
Multiply 6 x 6 = 36.
Move left to the next digit on the top line, but stay with the 6 on the
bottom line until you’ve finished with the top line.
www.kidsalgebra.com
6416843
In the answer 6 x 6 = 36, the 6 is a “Ten”. So 6 plus the 2 that you
“Carried” to the “Tens” column earlier gives you 6 + 2 = 8.
Carry the 3 to the “Hundreds” column from
6 x 6 = 36 and fill in the 6 + 2 = 8 “Tens”. x
www.kidsalgebra.com
6416
384
There are no more digits to the left of the 6 on the top line.
The 3 that you carried earlier is the only “Hundred” so you just need to
fill it in.No more digits.
x
www.kidsalgebra.com
6416
384
Next move one digit to the left on the bottom line.
The 1 in 16 is a “Ten”.
www.kidsalgebra.com
6416
384
Because the 1 in the 16 that you are about to multiply is a “Ten”, the “Singles” digit to the right in the
bottom line becomes a 0.
0
x
www.kidsalgebra.com
6416
384
Multiply 1 x 4 = 4 and write the 4 in the next place to the left of the 0.There are no “Hundreds” to carry.
40
x
www.kidsalgebra.com
6416
384
Stay with the 1 on the bottom line and move one digit left on the top line, multiply 1 x 6 = 6 and write it to the left of the 4.
640
Multiply 1 x 6 =
6.
www.kidsalgebra.com
6416
384
You’ve multiplied the two numbers making
these two lines below them.Next, add the two lines to get the
answer.
640v
+=
www.kidsalgebra.com
When you write 23 x 1,024 in a sentence you add a comma “,” after 3 digits to the
right.This makes it easier to read in a sentence.But when you multiply you want to keep your digits in their columns so you leave
out the “,” 102423
The number of tomato plants in each Garden = 1,024. Now you can do the 2nd Step: Number of tomato plants in
all 23 Gardens.
www.kidsalgebra.com
1st Step:
16 x 64 =
1,024
2nd Step:1,024 x 23
Answer: Total Plants
www.kidsalgebra.com
Remember Rule # 1: Always put the smallest number at the
bottom.
23 x 1,024 =23 is smaller than 1,024. 1024
23
www.kidsalgebra.com
Remember Rule # 2.Make one calculation line
for each digit in the bottom line.Starting with the digit to the right on the bottom line, multiply each digit in the top
line.You write the 2 in 3 x 4 = 12 in the “Singles”
column and carry the 1 “Ten”.x
1,02423
2
3 x 4 = 12
1
www.kidsalgebra.com
1,024 2372
6 + 1 = 7.
Multiply 3 x 2 = 6 and add 6 to the 1 that you carried and write 7 in the
“Tens” column.
www.kidsalgebra.com
This one is easy because any number multiplied by 0 always equals 0.
It doesn’t matter how big the number is. Even 1,000,000,000 x 0 = 0. So just write
3 x 0 = 0 in the “Hundreds” column.
x
1,02423
072
www.kidsalgebra.com
There are no more digits to the left of the 1 on the top line.
Move to the next digit to the left on the bottom line and go back to the
first digit to the right in the top line.
No more digits.x
102423
3072
www.kidsalgebra.com
Because the 2 in the 23 that you are about to multiply is a “Ten”, the “Singles” digit to the right in the
bottom line becomes a 0.
x 1024
233072
0
www.kidsalgebra.com
Multiply 2 x 4 = 8 and write the 8 in the next place to the left of the 0.There are no “Hundreds” to carry.
x 1024
233072
80
www.kidsalgebra.com
Stay with the 2 on the bottom line and move one digit left on the top line, multiply 2 x 2 = 4 and write it to the left of the 8.
102423
3072480
Multiply 2 x 2 = 4
www.kidsalgebra.com
Stay with the 2 on the bottom line and move one digit left on the top line, 2 x 0 = 0. Write 0 to the left of the 4.
102423
30720480
www.kidsalgebra.com
Stay with the 2 on the bottom line and move one digit left on the top line, 2 x 1 = 2. Write 2 to the left of the 0.
102423
30722048
0
www.kidsalgebra.com
You’ve multiplied the last digit to the left on both lines. So all that’s left is to add the two lines together to get your answer.
102423
3072+ 20480=
The number of tomato plants in each Garden = 1,024 and the number of tomato
plants in all 23 Gardens = 23,552. That’s the answer to the problem!
www.kidsalgebra.com
1st Step:
16 x 64 =
1,024
2nd Step:1,024 x 23= 23,552
Answer: Total Plants
=23,552
You can get a Wall Hanging at
www.kidsalgebra.com
to follow and practice your
multiplication.
www.kidsalgebra.com