DECIMALS ADDING or SUBTRACTING DECIMALS

DECIMALS
ADDING or SUBTRACTING DECIMALS
Place Value Chart
3
4
5
6
7
1
2
3
4
Example:
Ten-Thousandths
Thousandths
Hundredths
Ones
Tens
Hundreds
Thousands
Ten Thousands
Hundred thousands
Millions
.
Tenths
2
(and)
1
To add or subtract decimals, Line up the decimals – bring decimal
straight down. Add decimal at the end of whole numbers to fill gaps
Example:
54.03
 3.20
57.23
Example:
30 - 1.64 =
6.000
.345
+ 14.010
20.355
29 910

30.00
1.64
28.36
WRITING DECIMALS
To write a decimal in standard form, Look at the word after the number.
This word tells you where to put the last digit in the number. Using the
place value chart, write the numbers in the correct position in the chart.
Add zeros as placeholders to fill space between any number and the
decimal.
Example: 75 thousandths
MULTIPLYING DECIMALS
to multiply decimals, DO NOT LINE THE DECIMAL POINTS UP , count how
many numbers are behind the decimals in the problem. Place the decimal
the same number of spaces to the left in the answer. Add zeros if
necessary.
Example:
.
0
7
Example:
. 045
5
Ten-Thousandths
Thousandths
Hundredths
Tenths
(and)
Ones
Tens
Hundreds
Thousands
Ten Thousands
Hundred Thousands
Millions
DIVIDING DECIMALS
To divide a decimal by a whole number, move the decimal straight up
and divide as usual
Example:
To write a decimal in words, write the whole number in words. Write the
word and for the decimal point. Write the decimal part in words. Then
write the place name of the last digit.
Example:
= One and three hundred eight thousandths
= thirty-five hundredths
ROUNDING DECIMALS
To round decimals, locate the place value of the number being rounded,
look at the digit to the right of that place value. If the number is 5 or more,
add 1 to the place value number. If it is less than 5, the number stays the
same.
(move 3 spaces, add zero)
(move 3 spaces )
3.02
2 6.04
To divide a decimal by another decimal, move the decimal on the outside
to the end of the number. Then move the decimal the same number of
spaces on the inside
Example:
. 06 5.412
=
90.2
6 541.2
move 2 places
To divide a whole number by a decimal, place a decimal at the end of the
whole number first. Then move the decimal the same number of times as
you did on the outside. Add zeros to fill in the gaps.
Example: 0.2916 rounded to the nearest tenths place = 0.3
Example: 0.0916 rounded to the nearest hundredths place = 0.09
COMPARING DECIMALS
To compare decimals, line the decimals up. Starting from the left,
compare each number in each column. Any space that is blank in a
column, add a zero in its place.
less than
Example:
0.0027
0.0080
greater than
8 is bigger than 2
therefore: 0 .0027
= equal
0.008
.4 28.  .4 28.0
place decimal
at end of 28

7 0.
4 280.
move 1 space,
add a zero
To change a decimal to a percent, move the decimal 2 places to the right,
add the percent sign.
Example: 0.75 = 75%
Example: .6
= 60%