Place value: The value of a digit based on its position in a number. Each position represents a power of 10. The positions from right to left are: Ones, Tens, Hundreds, Thousands, Ten Thousands, Hundred Thousands, Millions.
- Identify the position of the digit from right to left
- Count the positions starting from 0 (ones place)
- Determine the place name based on the position
- Calculate the value by multiplying the digit by its place value
473,829
9(ones), 2(tens), 8(hundreds), 3(thousands), 7(ten thousands), 4(hundred thousands)
The digit 7 is in the fifth position from the right
The fifth position from the right is the ten thousands place
7 × 10,000 = 70,000
The digit 7 is in the ten thousands place and has a value of 70,000.
• Position counting: Count from right to left starting at position 0
• Place names: Ones, Tens, Hundreds, Thousands, Ten Thousands, Hundred Thousands
• Value calculation: Digit × Place value
Number names: Writing numbers using words instead of digits. For numbers up to 1,000,000, separate the hundreds, tens, and ones in each period (thousands and ones) and use hyphens for compound numbers like twenty-one.
642,817 has two periods: 642 (thousands) and 817 (ones)
642 = six hundred forty-two
six hundred forty-two thousand
817 = eight hundred seventeen
six hundred forty-two thousand eight hundred seventeen
Forty-two and seventeen are correctly hyphenated
Six hundred forty-two thousand eight hundred seventeen
• Period separation: Separate thousands from ones with comma
• Hyphenation: Use hyphens for compound numbers from 21-99
• Word order: Write thousands period first, then ones period
Expanded form: Writing a number as the sum of the values of each digit. Each digit is multiplied by its place value.
3 (hundred thousands), 5 (ten thousands), 7 (thousands), 4 (hundreds), 2 (tens), 8 (ones)
3 × 100,000 = 300,000
5 × 10,000 = 50,000
7 × 1,000 = 7,000
4 × 100 = 400
2 × 10 = 20
8 × 1 = 8
300,000 + 50,000 + 7,000 + 400 + 20 + 8
300,000 + 50,000 + 7,000 + 400 + 20 + 8 = 357,428 ✓
300,000 + 50,000 + 7,000 + 400 + 20 + 8
• Digit value: Each digit multiplied by its place value
• Sum of parts: All expanded parts should add up to the original number
• Place value: Correctly identify the value of each position
Place value: The value of a digit based on its position in a number. Each position represents a power of 10.
Period: A group of three digits in a number separated by commas. The main periods are ones, thousands, millions.
Expanded form: Writing a number as the sum of the values of each digit.
Standard form: Writing a number using digits.
Word form: Writing a number using words.
Comma placement: Commas separate periods in numbers, placed every three digits from right to left.
- Identify periods: Separate the number into groups of three digits
- Determine place values: Know the value of each position
- Read each period: Read the digits in each period as if they were in the ones period
- Add period names: Include "thousand" for the thousands period
- Combine periods: Read the entire number as a whole
• Each position is 10 times the position to its right
• Comma placement: Every three digits from right to left
• Period names: Ones, Thousands, Millions
• Compound numbers: Use hyphens (twenty-one, thirty-five)
• Zero handling: Zeros in middle positions are included in reading
• Value calculation: Digit × Place value = Digit's contribution
Comparing large numbers: Determining which of two or more large numbers is greater by comparing digits from left to right, starting with the highest place value.
523,741
523,809
Hundred thousands: 5 = 5, continue comparing
2 = 2, continue comparing
3 = 3, continue comparing
7 < 8, so 523,741 < 523,809
523,809 is greater than 523,741
523,809 is greater than 523,741 because in the hundreds place, 8 > 7.
• Left-to-right comparison: Start with the highest place value
• Digit-by-digit: Compare corresponding digits in the same place
• Stop when different: First differing digit determines the comparison
Large number subtraction: Finding the difference between two large numbers by aligning place values and subtracting corresponding digits, sometimes requiring regrouping.
742,601 > 742,583
742,601 - 742,583
742,601
- 742,583
Ones: 1 - 3 (need to borrow)
Tens: 0 - 8 (need to borrow)
Hundreds: 6 - 5 = 1 (after borrowing)
742,601 - 742,583 = 18
The second city has 18 more people
The second city has 18 more people than the first city.
• Place alignment: Align numbers by place value before subtracting
• Regrouping: Borrow from higher place values when needed
• Context: Interpret the difference in the problem's context
Place value: The value of a digit based on its position in a number. Each position represents a power of 10, with each position being 10 times the value of the position to its right.
Period: A group of three digits in a number, separated by commas. The main periods are ones, thousands, and millions.
Expanded form: Writing a number as the sum of the values of each digit (e.g., 357,428 = 300,000 + 50,000 + 7,000 + 400 + 20 + 8).
Standard form: Writing a number using digits (e.g., 357,428).
Word form: Writing a number using words (e.g., three hundred fifty-seven thousand four hundred twenty-eight).
Comma placement: Commas are placed every three digits from right to left to separate periods.
Compound numbers: Numbers from 21-99 that contain hyphens when written in words (e.g., twenty-one, thirty-five).
- Identify periods: Separate the number into groups of three digits using commas
- Determine place values: Know the value of each position (ones, tens, hundreds, thousands, ten thousands, hundred thousands)
- Read each period: Read the digits in each period as if they were in the ones period
- Add period names: Include "thousand" for the thousands period
- Combine periods: Read the entire number as a whole
- Apply conventions: Use hyphens for compound numbers, include zeros appropriately
• Each position is 10 times the value of the position to its right
• Comma placement: Every three digits from right to left
• Period names: Ones, Thousands, Millions
• Compound numbers: Use hyphens (twenty-one, thirty-five)
• Zero handling: Zeros in middle positions are included in reading
• Value calculation: Digit × Place value = Digit's contribution
• Comparison: Start from leftmost digit, compare corresponding positions
Visual Guide to Reading Numbers Up to 1,000,000
Hundred Thousands: 100,000
Ten Thousands: 10,000
Thousands: 1,000
Hundreds: 100
Tens: 10
Ones: 1
Example: 473,829
Separate periods with commas
Read each period separately
Add "thousand" for thousands period
Hyphenate compound numbers (21-99)
Example: 642,817 = Six hundred forty-two thousand eight hundred seventeen
Break into place values
Each digit × its place value
Add all parts together
Example: 357,428 = 300,000 + 50,000 + 7,000 + 400 + 20 + 8
Compare from left to right
Start with highest place value
First differing digit determines comparison
Example: 523,741 < 523,809 (because 7 < 8 in hundreds place)