Transcript Decimal Help

Decimal Help
This PowerPoint will help you get ready for the test!
Value of a Digit
What is the digit in question worth? If it’s a three in
the tenths place it’s worth three tenths or 0.3. Write
the answer in numerical form.
The value of the 9 in
7.895 is 0.09.
The 9 is in the hundredths spot. 9 X 1/100 =
0.09
Practice:
Find the value of the
underlined numbers.
1. 32.893
2. 4.075
3. 63.867
4. 1.004
Value of a Digit Answers
1.32.893 = 0.003
2.4.075 = 0.07
3.63.867 = 0.8
4.1.004 = 0.004
Writing Decimals Using Expanded Form
22.17 in expanded
form is
20 + 2 + 0.1 + 0.07
If you were to add those numbers up you
would get 22.17
Find the value of each digit and write it one
at a time with an addition sign between each
one.
Practice:
Write the following numbers in
regular expanded form.
5. 12.21
6. 0.135
7. 5.503
8. 0.018
Writing Decimals Using Expanded Form
Answers
5.
6.
7.
8.
12.21
0.135
5.503
0.018
=
=
=
=
10 + 2 + 0.2 + 0.01
0.1 + 0.03 + 0.005
5 + 0.5 + 0.003
0.01 + 0.008
Expanded Form Using Multiplication
Now that you can do regular expanded form,
let’s take it a step further. Take each number
and decide what you need to multiply by the
base number to make it using multiplication.
9.185 in expanded form multiplication is
(9 X 1) + (1 X 1/10) + (8 X 1/100) + (5 X 1/1000)
If you were to multiply what’s in each of
the parenthesis and add the products
together you would get a sum of 9.185.
Practice:
Write the following
numbers in expanded
form multiplication.
9. 62.783
10. 6.503
11. 0.185
12. 4.825
Expanded Form Using Multiplication Answers
9. 62.783 = (6 X 10) + (2 X 1) + (7 X 1/10) + (8 x 1/100) + (3 X 1/1000)
10. 6.503 = (6 X 1) + (5 X 1/10) + (3 X 1/1000)
11. 0.185 = (1 X 1/10) + (8 X 1/100) + (5 X 1/1000)
12. 4.825 = (4 X 1) + (8 X 1/10) + (2 X 1/100) + (5 X 1/1000)
Rounding Decimals
Round the
number below to
the nearest
hundredths
place.
3.241
The four is in the hundredths
place. The one to the right
says, “Leave it alone.” So, it
stays a 4.
Locate the number you’re asked to round to. You’ll have to know place
value (location) for this. Then, look to the right. My students like to
say, “Five and up bump it up. Four and below let it go.” That saying
means if the number to the right is a five or higher you bump the
number up one digit. If it’s a four or less, you don’t do anything to it.
Leave it alone.
The Answer is
3.240 or 3.24
All the numbers to the left
of the hundredths place
remain the same. The
numbers to the right of the
hundredths place become
zeroes.
Practice:
Round the following
numbers to the
hundredths place.
13. 7.625
14. 12.333
15. 30.002
16. 51.066
Rounding Decimals Answers
13. 7.625 = 7.630 or 7.63
14. 12.333 = 12.330 or 12.33
15. 30.002 = 30.00 or 30
16. 51.066 = 51.070 or 51.07
Finding the Place Value of the Digit (Aka
Location)
In class we did a cheer. We said, “Ones,
tenths, hundredths, thousandths.”
123
Practice:
Name the location of the
underlined digit.
17. 32.893
18. 75.618
19. 63.867
20. 29.912
The 2 is in the
hundredths
place.
Finding the Place Value of the Digit (Aka
Location) Answers
17.
18.
19.
20.
32.893
75.618
63.867
29.912
=
=
=
=
thousandths
tenths
hundredths
hundredths
Writing Numbers in Word Form
The number 456 is four hundred
fifty-six. The last spot is
thousandths, so my last word is
thousandths.
12.456
is twelve AND four
hundred fifty-six
thousandths
Read the numbers to the left of the decimal
how you would normally read them. When
you see the decimal say, “AND.” Read the
numbers to the right of the decimal as a
group. Then say the last spot’s name.
“Last spot
last
word!”
Practice:
Write the following
numbers in word form.
21. 67.015
22. 522.04
23. 771.771
24. 84.97
Writing Numbers in Word Form Answers
21.
22.
23.
24.
67.015 = sixty-seven and fifteen thousandths
522.04 = five hundred twenty-two and four hundredths
771.771 = seven hundred seventy-one and seven hundred seventy-one thousandths
84.97 = eighty-four and ninety-seven hundredths
Comparing Decimals
7.2
>
7.2
7.02
7.02
“The alligator eats the biggest number.”
The number one tip I can give you is to
line your decimals up then compare the
numbers to determine which number is
bigger or smaller.
They both have sevens, but the
tenths place is different. Two
is bigger than zero, so 7.2 is
the bigger number.
Practice:
Compare the two numbers
using <, >, or =.
25. 0.21
0.211
26. 40.99
40.9
27. 6.22
6.220
28 9.44
9.4
Comparing Decimals Answers
25. 0.21
26. 40.99
27. 6.22
28. 9.44
<
>
=
0.211
>
9.4
40.9
6.220
Creating a Base Ten Block Display of a
Decimal
You need to be able to recreate
a base ten block (10 X 10).
58 of the 100 blocks are shaded, so 0.58
is shaded.
Vocabulary to Know
Standard Form – A way to write numbers by using the digits 0 – 9, with each
digit having a place value. E.g., 456
Expanded Form – A way to write numbers by showing the value of each
digit. E.g., 832 = 800 + 30 + 2
Word Form – A way to write numbers in standard English. E.g., 4,829 = four
thousand eight hundred twenty-nine
Digit – Any one of the ten symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 used
to write numbers.