Download Multiplication and Division

Multiplication and
Division
Multiplication
Here are some rules that will help you with
multiplication problems:
• The order of the numbers does not matter in a
multiplication problem:
4x5=5x4
• Any number multiplied by 1 is equal to that
number:
6,798 x 1 = 6,789
• Any number multiplied by 0 is equal to zero!
6,798 x 0 = 0
Multiplying two numbers
65 x 8
Rewrite the problem
so the digits in the
ones place are in a line:
Multiply the digits
in the ones place:
Place the 0 in the ones
column and carry the 4.
65
8
4
65
8
0
Now multiply the 8 by the 6 in the 65.
8 x 6 = 48. Add in the 4 that was
leftover from the ones column.
4
65
48 + 4 = 52. Write that number
below the line, to the left of
the ones place.
8
So, 65 x 8 = 520!
520
What if you have two digit numbers?
43 x 78
Again, line up
the numbers.
43
 78
2
Start in the ones column: 8 x 3 = 24.
Write the 4 below the line and
carry the 2 to the tens column.
43
 78
4
Now multiply
the 8 in the ones place
by the 4 in the tens place.
Be sure to add in the 2
that you carried over
from before.
It is 8 x 4 = 32 + 2 = 34
2
43
 78
344
Now do it all over again, but
working with the 7 in the tens place.
Put a zero in the ones place below
the 4.
2
43
 78
344
3010
7 x 3 =21. Place the 1 in
the tens place and carry the 2.
Then multiply 7 x 4. This is equal to 28. Add in
the 2 to get 30. Write this to the left of the 1.
Finally, add up the columns to find the solution.
43
 78
344
 3010
3354
43 x 78 = 3354
Division
There are three parts to a division problem.
The first is the dividend. The dividend is the
number that is being divided.
The next is the divisor. The divisor is the
number that is used to divide another
number.
The answer is the quotient.
So, in the problem a ÷ b = c, a is the dividend,
b is the divisor, and c is the quotient.
A Few Division Rules
• The order of the numbers does matter in
division.
21 ÷ 3 ≠ 3 ÷ 21
• Any number divided by 1 is equal to that
number.
34 ÷ 1 = 34
• Any number divided by 0 is not defined. There
is no answer.
560 ÷ 0 = ???
Divide 2736 by 2
Set up the problem like this:
2 2736
The first digit divides equally. 2 ÷ 2 = 1. So
place the 1 above the 2 in the dividend.
1
2 2736
•Look at the next number. 2 will go into 7 three
times because 2 x 3 = 6.
•Place the 3 above the 7.
•Multiply 3 x 2 and place that answer
under the 7.
13
•Subtract 6 from 7 and
2 2736
write the answer below.
6
1
•Bring down the 3 so that you are
now looking at a dividend of 13.
•How many times does 2 go into 13?
It goes in 6 times (2 x 6 = 12).
136
•Place the 6 above the 3 under
2 2736
the division sign. Multiply
6
that 6 by 2 and write the number
13
under 13.

12
•Subtract and bring down the
16
6 in the ones place.
•Now do it one more time.
136 8
•How many times does
2 2736
2 go into 16? It goes in 8 times.  6
(2 x 8 = 16.)
13
 12
•Place the 8 above the 6
16
under the division sign,
 16
and you are done!
0
2736 ÷ 2 = 1368!
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