DecimalsMr. Walker

What is a Decimal?

It is a dot after a number.Every whole number has a decimal on the

end, even if it is not shown.A decimal means that the digits after it are

less than one whole. Just part of something bigger.

A dollar is a whole. Fifty cents is just part of a dollar.

.

25 356 122. . .

25 75. Means there are 25 and a little more, but not quite 26

1.. 50

Place Value Reading a Number with a Decimal

652.94

6 5 2 9 4

Six hundred fifty-two and ninety-four hundredths

Always use ‘and’ for the decimal

Place Value Reading a Number with a Decimal

142.4

1 4 2 4

One hundred forty-two and four tenths

Place Value Reading a Number with a Decimal

957.03

9 5 7 0 3

Nine hundred fifty-seven and three hundredths

Comparing Decimals

Think Money!!If it does not look like money, then make it

look like money by adding a zero at the end.

84.5 84.05

>,<, or =

Add a zero to the number on the left to make it comparable, or

to make it look like money0

Which one would you rather have in your bank account?

>

Remember, the alligator always eats the bigger number.

Comparing Decimals (Try it)

39.2 39.02

>,<, or =

0 >Answer

Add a zero

5.09 5.90<Answer

Add a zero

12.20 13.20<Answer

Add a zero

52.3 52.300 =Answer

Add a zero

Adding and Subtracting Decimals

When adding or subtracting decimals, you only need to remember two things…

Line up the decimalsPut zeros in all the empty spaces

12.4 + .35 + 5.01 12.4 .35+ 5.01

12.40 00.35+05.0117.76

Don’t forget to bring down the decimal

Adding & Subtracting Decimals (Try)

12.2 + 6.05 + .1

12.2006.05

+00.10

18.35

Answer

125.3 – 118.05

125.30-118.05

7.25

Answer

1.72 + .01 +.6

1.720.01

+0.60

2.33

Answer

Multiplying Decimals

Multiplying decimals is very easy Ignore the decimals until you are done

1.29x 6.5

129x 65645

+77408385

Then count all the digits to the right of both decimals. That number is the amount of spaces from the right (in your answer) you will put your decimal

1 2 3

.

Dividing Decimals

Dividing decimals is very easy Just ignore it at first and do the problem Then put the decimal (in your answer) right above where

it is in the problem. 2 7.9 4 6 1 9 1 8 1 4 1 4 0

3.8 7

Decimals are Fractions (money)

.25 is the same as ¼ (4 quarters make a whole dollar, but I only have one of them, which equals 25 cents.)

.50 is the same as ½ (4 quarters make a whole dollar, but I only have two of them, which equals 50 cents or half a dollar.)

.75 is the same as ¾ (4 quarters make a whole dollar, but I only have three of them, which equals 75 cents.)

15.75 is the same as 15 ¾ (Fifteen dollars and three quarters or 75 cents.)

Decimals are Fractions (others)

You can find the fraction of any decimal based on place value.

.34 is the same as 34/100 (the .34 goes into the hundredths place)

.6 is the same as 6/10 (.6 only goes to the tenths place)

.05 is the same as 5/100 (.05 goes to the hundredths place)

3 460 5

Try Finding the Fractions from the Decimals

.34 2.4 3.06

34100

3 4

.34 goes into the hundreths spot, so the denominator is a hundred.

Answer

410

61002 3

Answer Answer

The 2 is a whole number and will go to the left of the fraction.

Try Finding the Decimals from the Fractions

.23 7.5 4.02

23100

2 3

Answer

510

21007 4

Answer Answer

23 is over a hundred. Put 23 into the chart so that the 3 is in the hundreths spot.You could also say that since 100 has 2 zeros, all you need to do is write 23 and move the decimal (at the end of every whole number) two spaces to the left.