Transcript Place Value Review and Background

Math – Review & Practice
Place Value
What are digits?

Digits are the numbers…
Together, they can be combined to make up all of the numbers.
What is place value?

Place value is the value given to the place a
digit has in a number.
For example: Look at the number 3,056.
The 5 is in the ten’s place, so it’s value equals 50.
You try! Look at the number 14,289.
What is the value of the underlined digit?
The 4 is in the thousands place, so the value is
4,000.
What is the value of the underlined
digit?
1. 14,768
700
2. 256,201
1
3. 134,783
30,000
4. 845,682
5,000
5. 614,503
600,000
6. 1,234,568,245
200,000,000
What is a period in math?

A period is a group of three digits in a
number, separated by a comma.
Thousands Period
Ones Period
Get a pencil and write the numbers
below in standard form.
Two hundred four million, one hundred one
40,000,000 + 30,000 + 200 + 8
Write the numbers below in
expanded form.
1. One thousand, two hundred twenty-five
2. 543,031
3. Fifty billion, two hundred eight
Write the word name for the
numbers below.
1.
25,658,012,041
Twenty-five billion, six hundred fiftyeight million, twelve thousand, forty-one
2.
237,984.02
Two hundred thirty-seven thousand,
nine hundred eighty-four and two
hundredths
Place Value Relationships
Place Value Relationships
Place Value Relationships
Place Value Relationships
Place Value Relationships
Place Value Relationships
Comparing Numbers
What does it mean to compare?
You are deciding which of 2 numbers is greater.
Step 1: Check to see if there are the same number of digits.
Step 2: If not, the number with more digits has a greater value.
The first number has 5 digits.
The second number has 4 digits.
5 digits > 4 digits
So, 28,462 > 2,846
Or, 2,846 < 28,462
Comparing Numbers
What does it mean to compare?
You are deciding which of 2 numbers is greater.
Step 1: Begin at the left if there are the same number of digits.
Compare.
Step 2: Find the 1st place the digits differ. Compare.
Both numbers have an 8 in the thousands place.
Both numbers have a 1 in the hundreds place.
9 tens > 8 tens
So, 8,193 > 8,186
Or, 8,186 < 8,193
You try it! Compare.
1. 456
465
2. 54,193
54,183
3. 125
152
4. 167,465
167,465
Ordering Numbers
What does it mean to order numbers?
You are placing the numbers from least to greatest or greatest to least.
Exploring Rounding
1. What does estimate mean?
It means to find a number close to the exact number.
2. What does rounding mean?
It means replacing a number with a number that tells
about how many or how much. (Rounding is a way
to estimate.)
Round 56 to the nearest ten.
56
When I count by tens, 56 is between 50 and 60.
So, my answer is either 50 or 60.
56 is closer to 60, so my answer is 60.
Round 35 to the nearest ten.
35
When I count by tens, 35 is between 30 and 40.
So, my answer is either 30 or 40.
35 is halfway to 40, so my answer is 40.
Round 517 to the nearest hundred.
517
When I count by hundreds, 517 is between 500 and 600.
So, my answer is either 500 or 600.
517 is closer to 500, so my answer is 500.
Round 968 to the nearest hundred.
968
When I count by hundreds, 968 is between 900 and 1,000.
So, my answer is either 900 or 1,000.
968 is closer to 1,000, so my answer is 1,000.