1. Line ‘em up or Count ‘em up
Decimals
Line ‘em up or Count ‘em up

2. Unit Overview By the end of this unit, you should be able to:
Represent decimals on a number line
Compare and order decimals
Round decimals
Use estimation to approximate an answer
Add, subtract, multiply, and divide decimals

3. Representing Decimals
Numbers to the right of the decimal point are called decimals. Decimals represent numbers that have a value between to whole numbers.

4. Write a Decimal in Word Form
17.542
Seventeen
and
five hundred forty-two
thousandths
To write in word form, follow these steps:
Write the number to the left of the decimal.
Write “and” where the decimal point is.
Write the number that is to the right of the decimal point.
Write the place value of the digit furthest to the right.

5. Write a Decimal in Word Form
8 2 5
.825
eight hundred twenty-five
thousandths
To write in word form, follow these steps:
Write the number to the left of the decimal.
Write “and” where the decimal point is.
Write the number that is to the right of the decimal point.
Write the place value of the digit furthest to the right.

6. Write a Decimal in Word Form
16.08
Seventeen
and
eight
hundredths
To write in word form, follow these steps:
Write the number to the left of the decimal.
Write “and” where the decimal point is.
Write the number that is to the right of the decimal point.
Write the place value of the digit furthest to the right.

7. Your Turn – Write these decimals in word form
1) 7.17
seven and seventeen hundredths
2) .068
sixty-eight thousandths 3)
nine and seven hundred sixty-nine ten-thousandths
Tips
Only put hyphens (-) in the numbers 21 through 99
Don’t use commas
Be sure of your place value

8. Write a decimal in standard form
Standard form is just the usual way we write numbers.
Thirty-five and ninety-six ten-thousandths
3 5
0 0 .
9 6

9. Your Turn
Write three and eighty-five thousandths in standard form Write five tenths in standard form. 0.5 Write forty-one and sixty-two hundredths in standard form

10. Your turn – Challenge problem
Write this number in standard form: one hundred two ten-thousandths
*Remember the word “AND”!
one hundred AND two ten-thousandths=
Totally different!

11. Write a decimal in Expanded form
Expanded form is a sum of the products of each digit and its place value. (???) Basically, take each digit of the number and multiply it by its place value position. Then add all of those up. For example:  Take the 3 times 10 because it is in the tens place. + Take the 2 times 1 because it is in the ones place. + Take the 1 times .1 because it is in the tenths place. + Take the 4 times .01 because it is in the hundredths place. Looks like this: (3 x 10) + (2 x 1) + ( 1 x .1) + (4 x .01)
When you solve it, you get the original number:
(3 x 10) + (2 x 1) + ( 1 x .1) + (4 x .01)
(30) (2) (.1) (.04)
32.14

12. Your Turn- Write this number in expanded form
Eleven and three tenths 11.3

13. Your Turn- Write this number in expanded form
Two and five hundredths 2.05

14. Your Turn- Write this number in expanded form
Thirty-four and sixteen hundredths 34.16