Place Value: Understanding the value of each digit based on its position in a number. Each position represents a power of 10.
Rounding: Approximating numbers to make them easier to work with by replacing them with nearby numbers that are multiples of 10, 100, 1000, etc.
Digit: Any of the numerals 0-9 used to form numbers.
Place Value: The value of a digit based on its position in a number (ones, tens, hundreds, etc.).
Face Value: The actual value of a digit regardless of its position.
Rounding: Replacing a number with another number that tells about how many or how much.
Expanded Form: Writing a number as the sum of the value of each digit.
Standard Form: Writing a number in the normal way using digits.
• Place Value Pattern: Ones, Tens, Hundreds, Thousands, Ten Thousands... Each place is 10 times the previous place
• Rounding Rule: Look at the digit to the right of your target place: 5 or more rounds UP, 4 or less rounds DOWN
• Zero Replacement: After rounding, all digits to the right of the target place become zeros
• Comparison Method: Compare numbers from left to right, starting with the highest place value
• Expanded Form: Each digit multiplied by its place value and added together
- Identifying Place Value: Locate the position of each digit from right to left
- Understanding Relationships: Know that each place is 10 times the next lower place
- Applying Rounding Rules: Look at the digit to the right of the target place
- Verifying Results: Check if rounded number makes sense in context
- Comparing Numbers: Start from the leftmost digit and work right
- Writing Expanded Form: Multiply each digit by its place value and add
a) 87,342 (underline the 7)
b) 52,691 (underline the 2)
c) 94,058 (underline the 0)
a) In 87,342, the 7 is in the thousands place. Its value is 7 × 1,000 = 7,000
b) In 52,691, the 2 is in the thousands place. Its value is 2 × 1,000 = 2,000
c) In 94,058, the 0 is in the hundreds place. Its value is 0 × 100 = 0
a) 63,847 to the nearest ten
b) 49,256 to the nearest hundred
c) 71,583 to the nearest thousand
a) 63,847 to nearest ten: Target is tens place (4), deciding digit is ones place (7). Since 7 ≥ 5, round UP → 63,850
b) 49,256 to nearest hundred: Target is hundreds place (2), deciding digit is tens place (5). Since 5 ≥ 5, round UP → 49,300
c) 71,583 to nearest thousand: Target is thousands place (1), deciding digit is hundreds place (5). Since 5 ≥ 5, round UP → 72,000
a) 54,721 _____ 54,271
b) 83,649 _____ 83,649
c) 62,158 _____ 62,518
a) 54,721 > 54,271 (compare from left: same in ten thousands and thousands, then 7 > 2 in hundreds)
b) 83,649 = 83,649 (identical numbers)
c) 62,158 < 62,518 (same in ten thousands and thousands, then 1 < 5 in hundreds)
a) 75,392
b) 48,061
c) 92,740
a) 75,392 = 70,000 + 5,000 + 300 + 90 + 2
b) 48,061 = 40,000 + 8,000 + 0 + 60 + 1
c) 92,740 = 90,000 + 2,000 + 700 + 40 + 0
a) 58,743
b) 92,568
c) 34,821
a) 58,743: Nearest ten = 58,740, Nearest hundred = 58,700, Nearest thousand = 59,000
b) 92,568: Nearest ten = 92,570, Nearest hundred = 92,600, Nearest thousand = 93,000
c) 34,821: Nearest ten = 34,820, Nearest hundred = 34,800, Nearest thousand = 35,000
63,847, 63,487, 63,748, 63,478
All numbers have 6 in ten thousands and 3 in thousands, so compare hundreds place:
63,487 and 63,478 have 4 in hundreds
Between 63,487 and 63,478: 7 < 8 in tens, so 63,478 < 63,487
Between 63,748 and 63,847: 7 < 8 in hundreds, so 63,748 < 63,847
Order: 63,478 < 63,487 < 63,748 < 63,847
63,478, 63,487, 63,748, 63,847
To make the largest number, arrange digits from greatest to least: 97,431
To make the smallest number, arrange digits from least to greatest: 13,479
Note: We cannot start with 0 (which we don't have anyway), so 1 is the smallest possible first digit
Largest: 97,431, Smallest: 13,479