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Number and Place Value - Comparing and Ordering Large Numbers

Grade 4IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Place Value Positions: To compare large numbers, you must understand the value of each digit. For a six-digit number, the positions from left to right are Hundred Thousands (100,000100,000), Ten Thousands (10,00010,000), Thousands (1,0001,000), Hundreds (100100), Tens (1010), and Ones (11). Imagine a place value chart where each column to the left is 1010 times larger than the column to its right.

Counting Digits Rule: The simplest way to compare two numbers is to count their digits. A number with more digits is always greater than a number with fewer digits. For example, 10,23410,234 (5 digits) is automatically larger than 9,9889,988 (4 digits) because it reaches the Ten Thousands place while the other only reaches the Thousands place.

Comparing Left to Right: When two numbers have the same number of digits, compare them digit by digit starting from the highest place value (the far left). If the digits in the highest place are the same, move one position to the right and compare those digits. Continue this process until you find a difference.

Comparison Symbols: We use specific symbols to show the relationship between numbers. The 'Greater Than' symbol (>>) points its open side toward the larger number. The 'Less Than' symbol (<<) points its vertex toward the smaller number. The 'Equal To' symbol (==) is used when the numbers have the exact same value in every place.

Ascending Order: This means arranging numbers from the smallest to the largest value. Visualise this as climbing up a staircase, where each step represents a larger number (1,2345,67810,1111,234 \rightarrow 5,678 \rightarrow 10,111).

Descending Order: This means arranging numbers from the largest to the smallest value. Visualise this as walking down a staircase, starting from the highest value and moving down to the lowest (50,00040,00030,00050,000 \rightarrow 40,000 \rightarrow 30,000).

Number Line Representation: On a horizontal number line, numbers increase as you move from left to right. If number AA is to the right of number BB, then A>BA > B. This visual tool helps in identifying which large numbers are closer to certain milestones, such as the nearest 10,00010,000 or 100,000100,000.

📐Formulae

a>b (a is greater than b)a > b \text{ (a is greater than b)}

a<b (a is less than b)a < b \text{ (a is less than b)}

a=b (a is equal to b)a = b \text{ (a is equal to b)}

10×10,000=100,00010 \times 10,000 = 100,000

10×1,000=10,00010 \times 1,000 = 10,000

💡Examples

Problem 1:

Compare the numbers 564,321564,321 and 564,702564,702 using the correct comparison symbol.

Solution:

Step 1: Count the digits. Both numbers have 66 digits. Step 2: Compare from left to right. Hundred Thousands: Both have 55 (500,000500,000). Ten Thousands: Both have 66 (60,00060,000). Thousands: Both have 44 (4,0004,000). Hundreds: The first number has 33 (300300) and the second has 77 (700700). Since 300<700300 < 700, then 564,321<564,702564,321 < 564,702.

Explanation:

By comparing each place value from left to right, we found the first difference in the hundreds place, which allowed us to determine the relationship.

Problem 2:

Order the following numbers in ascending order: 87,40587,405; 8,9998,999; 87,45087,450; 87,09987,099.

Solution:

Step 1: Identify the smallest number by counting digits. 8,9998,999 has 4 digits, while the others have 5. So, 8,9998,999 is the smallest. Step 2: Compare the remaining 5-digit numbers starting from the left. All three have 88 in the Ten Thousands and 77 in the Thousands place (87,00087,000). Step 3: Compare the Hundreds place: 87,09987,099 has 00 hundreds, 87,40587,405 has 44 hundreds, and 87,45087,450 has 44 hundreds. So, 87,09987,099 is the next smallest. Step 4: Compare the remaining two: 87,40587,405 vs 87,45087,450. Look at the Tens place. 0<50 < 5. So 87,40587,405 is smaller than 87,45087,450. Final Order: 8,999<87,099<87,405<87,4508,999 < 87,099 < 87,405 < 87,450.

Explanation:

Ascending order means smallest to largest. We first used digit count to find the smallest, then compared place values for the rest.