1. Decimal Notation
Decimals represent part of a whole number. Like whole numbers there are different place values of decimals and they can be written several ways.

2. Decimal Notation

3. Decimal Notation
Word Form- Write the whole number, use the word “and” in place of the decimal, write the decimal portion.
Example: “Forty-three and two hundred seventy-five thousandths”

4. Decimal Notation
Number Form- Write using digits in the correct place value.
Example: “Five and twelve hundredths” = 5.12
Expanded Form- Write an addition problem using the value of each digit.
Example:

5. Rounding Decimals Underline place value you are rounding to
Look at the digit to the right
If it is 4 or less the underlined digit stays the same
If it is 5 or more the underline digit goes up one
The digits to the left stay the same, the digits to the right get dropped/turn to zeros

6. Comparing & Ordering Fractions
> Greater Than
< Less Than
= Equal To
Compare whole #’s first
If the whole #’s are the same, compare decimals starting at the left

7. Scientific Notation Scientific Notation
Where a number is written in two parts: First: just the digits (with the decimal point placed after the first digit), Followed by: ×10 to a power that would put the decimal point back where it should be.

8. Scientific Notation To Change from Number Form to Scientific Notation:
Move the decimal to the left until the whole # is between 1 & 9
Take that # times 10, with an exponent (the exponent should be the number of places you moved the decimal)

9. Scientific Notation To Change from Scientific Notation to Number Form:
Look at the exponent
Move the decimal that many places to the right.

10. Add/Subtract Decimals
Line up the decimals
Add/Subtract like normal

11. Multiply Decimals Multiply like normal
Count the number of digits behind the decimals in the problem. There should be the same number of digits behind the decimal in the product.

12. Divide Decimals by Whole Numbers
Move the decimal point straight up
Divide like normal

13. Divide Decimals by Decimals
Move the decimal to the end of the divisor
Move the decimal the same # of places right in the dividend
Move the decimal straight up.
Divide like normal