Adding and subtracting numbeDecimals.ppt

About decimals

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
00

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.
-15.9 1 1
Add zeros to
line up
everything,
then
subtract
000
799
80.21 9

7. Try This!
41.
- 25.45