Dividing by Decimals - American Baccalaureate Schoolhandouts.abs.edu.kw/mshs/Assignments...

Dividing by Decimals

Dividing decimals is a lot like

dividing by a whole number.

There is just one thing you need

to remember before dividing:

You have to make the number

outside the house (divisor) a

whole number (A number

without a decimal).

Division Vocabulary

64.122.

“Inside”

Dividend

“Outside”

Divisor

“Roof”

Quotient

Division Vocabulary

64.122.

12.64 ÷ .2

12.64 divided by .2

Steps in Dividing Decimals

1. Make the divisor (outside number) a whole number by

moving (swingin’) the decimal to the right as many places as

it takes to make it a WHOLE NUMBER.

2. In MONKEY TERMS: Whatever the outside monkey does

(how far it swings) the inside monkey does also. Then the

monkey climbs up and sits on the roof!

It’s simple, move the decimal to

the right until it is at the end of

the number.

Here’s the problem: 1.1 ) 6.3

Move the decimal to the right until you

are at the end of the number. In this

case, we only had to move it once.

1.1 ) 6.3

Since we moved the decimal on the divisor (#

outside the house) we HAVE TO move the

decimal in the dividend the same number of

times. In this case it would also be one time.

Our new problem

becomes:

11. ) 63.

11 ) 63

Or

11 ) 63

Now we just divide like

we always do:

What happens if we have a

decimal in the divisor and not

the dividend?

2.14 ) 797

2.14 ) 797

Just remember, the dividend is a

whole number so there is a

decimal at the end of the

dividend that is not there.

2.14 ) 797.The decimal

would go here

since the number

is whole. You

would still have

to move it two

places to the

right.

Is really…

You try this one:

3.4 ) 30.6

You try this one:

.26 ) 3.38

You try this one:

2.5 ) 400

You try this one:

3.21 ) 5.136

Steps in Dividing Decimals –

Swingin’ Monkeys

64.122.

Steps in Dividing Decimals –

Swingin’ Monkeys

64.122.

3. Place (swing) the decimal point in the answer (quotient)

lined up with the decimal point in the dividend (on the roof).

Steps in Dividing Decimals

4. Now, divide as usual!

4.1262

Steps in Dividing Decimals

4. Divide the numbers. Make sure the decimal point stays

lined up.

4.12626

126

2

6

4

3

What is actually happening . . .

• When you move the

decimal one place to

the right to create a

WHOLE number –

you are actually

multiplying it by 10!

• When you move the

decimal two places to

the right to create a

WHOLE number –

you are actually

multiplying it by 100!

• Three?

Your Turn - Practice

1) 14.2 ÷ 0.2 =

2) 25.5 ÷ 1.5 =