Place Value: The value of a digit based on its position in a number
Rounding: Approximating a number to the nearest ten, hundred, or thousand
Digit: Any of the numerals 0-9
- Identify place value: Locate the position of each digit
- Understand relationships: Know that each place is 10 times the next lower place
- Apply rounding rules: Look at the digit to the right of the target place
- Verify results: Check if rounded number makes sense
• Place Value Pattern: Ones, Tens, Hundreds, Thousands, Ten Thousands...
• Rounding Rule: Look at digit to the right - 5+ rounds up, 4- rounds down
• Value Relationship: Each place is 10 times the previous place
• Zero Replacement: Digits to the right become zeros after rounding
Place Value: The value of a digit based on its position in a number. Each position represents a power of 10.
- Start from the rightmost digit (ones place)
- Move left, increasing the place value by powers of 10
- Write the expanded form by multiplying each digit by its place value
5 is in the thousands place = 5 × 1,000 = 5,000
8 is in the hundreds place = 8 × 100 = 800
3 is in the tens place = 3 × 10 = 30
7 is in the ones place = 7 × 1 = 7
5,837 = 5,000 + 800 + 30 + 7
5,837 = (5 × 1,000) + (8 × 100) + (3 × 10) + (7 × 1)
5 is in thousands place (value: 5,000), 8 in hundreds (800), 3 in tens (30), 7 in ones (7)
Expanded form: 5,837 = 5,000 + 800 + 30 + 7
• Positional notation: Each position has specific value
• Place value pattern: Each place is 10 times the previous
• Expanded form: Shows value of each digit separately
Rounding to nearest ten: Finding the closest multiple of 10 to a given number.
- Identify the tens digit (second from right)
- Look at the ones digit (rightmost)
- If ones ≥ 5, round up; if ones ≤ 4, round down
- Change all digits to the right to zero
We want to round to the nearest ten, so look at the tens digit (6)
The digit to the right of tens is the ones digit (7)
Since 7 ≥ 5, we round up. Increase the tens digit by 1 (6 + 1 = 7)
Change all digits to the right of tens to zero: 4,870
4,867 rounded to the nearest ten is 4,870
• Rounding rule: 5 or more rounds up, 4 or less rounds down
• Target place: Identify which place to round to
• Deciding digit: Look at digit immediately to the right
Rounding to nearest hundred: Finding the closest multiple of 100 to a given number.
- Identify the hundreds digit (third from right)
- Look at the tens digit (second from right)
- If tens ≥ 5, round up; if tens ≤ 4, round down
- Change all digits to the right to zero
We want to round to the nearest hundred, so look at the hundreds digit (4)
The digit to the right of hundreds is the tens digit (2)
Since 2 ≤ 4, we round down. Keep the hundreds digit the same (4)
Change all digits to the right of hundreds to zero: 7,400
7,428 rounded to the nearest hundred is 7,400
• Rounding rule: 5 or more rounds up, 4 or less rounds down
• Target place: Identify which place to round to
• Deciding digit: Look at digit immediately to the right
Comparing numbers: Determining which number is greater, lesser, or equal by comparing digits from left to right.
- Compare digits starting from the leftmost (highest place value)
- If digits are equal, move to the next place value
- The first place where digits differ determines the greater number
Both numbers have 3 in thousands place, so continue to next place
Both numbers have 5 in hundreds place, so continue to next place
3,572 vs 3,527 → 7 > 2
Since 7 > 2 in the tens place, 3,572 > 3,527
3,572 is greater than 3,527
• Left-to-right comparison: Start with highest place value
• Place value importance: Higher places matter more
• Difference detection: First differing digit determines outcome
Rounding to nearest thousand: Finding the closest multiple of 1,000 to a given number.
- Identify the thousands digit (fourth from right)
- Look at the hundreds digit (third from right)
- If hundreds ≥ 5, round up; if hundreds ≤ 4, round down
- Change all digits to the right to zero
We want to round to the nearest thousand, so look at the thousands digit (8)
The digit to the right of thousands is the hundreds digit (6)
Since 6 ≥ 5, we round up. Increase the thousands digit by 1 (8 + 1 = 9)
Change all digits to the right of thousands to zero: 9,000
8,642 rounded to the nearest thousand is 9,000
• Rounding rule: 5 or more rounds up, 4 or less rounds down
• Target place: Identify which place to round to
• Deciding digit: Look at digit immediately to the right