To add and subtract decimals: 1) Line up the decimals by writing zeros in empty decimal places as needed. 2) Add or subtract the numbers as usual, carrying or borrowing across the decimal. 3) The decimal point belongs in the answer in the same column as in the original numbers.

1. Adding and
Subtracting Decimals

2. Essential Question:
• How do I add and subtract decimals?
• Always line up decimals
• Add and subtract like you always do
• Bring decimal straight down in your
answers

3. Adding
Examples:
4.55 + 11.3
Put the first number on
the top of the second
number and line up the
decimals.
4.55
+ 11.3
You can
add a zero
to help
keep
everything
lined up
0
15.85
When adding
or subtracting
you always
start from the
right and work
left.

4. 6.44 + 16
When there is
not a decimal
put one
behind the
number.
Line up
the
decimal
6.44
+ 16.
Add a
zero to
line up
everythin
g
22.44
0

5. Subtracting
Examples:
5.34 -2.08
Put the first number on
the top of the second
number and line up the
decimals.
5.34
-2.08
3.26
Different signs
Take difference

6. 28 – 15.911
When there
is
not a decimal
put one
behind the
number.
28.
-15.911
Add zeros to
line up
everything,
then
subtract
000
7 9 9
8
0
.
2
1 9