6Comparing and Ordering Numbers

Comparing and Ordering Numbers

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When working with large numbers, we need to compare them to see which is greater, less than, or equal to another. Place value is our key tool for making these comparisons. Just like we learned to read and write large numbers using place value, we can use the same understanding to put numbers in order from smallest to largest or compare any two numbers.

Tip

Quick reminder: In place value, each position represents a different power of 10. From right to left: ones, tens, hundreds, thousands, ten-thousands, hundred-thousands, and so on. The leftmost digit has the highest value!

Comparing and Ordering Numbers · 1:26

**Comparing Numbers**: The process of determining which of two or more numbers is greater, less than, or equal to the others using place value and inequality symbols (<, >, =).

To compare numbers effectively, we start by looking at the leftmost digits (the highest place values) and work our way right until we find a difference. This is similar to how we alphabetize words by comparing letters from left to right.

Tip

Important rule: A number with more digits is always greater than a number with fewer digits (when both are positive whole numbers). For example, 1,000 > 999, even though 9 > 1!

Worked Example

Problem

Compare 34,567 and 34,592. Which number is greater?

Solution

34,592 > 34,567

Explanation

When comparing numbers, we only need to compare until we find the first place where the digits are different. Since 6 < 9 in the tens place, 34,567 is less than 34,592.

Tip

Remember: When comparing numbers with the same number of digits, start from the left and compare digit by digit. As soon as you find a difference, you can determine which number is greater without looking at the remaining digits!

Worked Example

Problem

Put these numbers in order from least to greatest: 125,400; 98,750; 125,040; 200,300

Solution

98,750 < 125,040 < 125,400 < 200,300

Explanation

When ordering multiple numbers, it helps to first separate them by the number of digits, then compare within each group using place value from left to right.

We can also use number lines to visualize comparisons. Numbers to the right on a number line are always greater than numbers to the left.

**Inequality Symbols**: Mathematical symbols used to show the relationship between numbers: < means 'less than', > means 'greater than', = means 'equal to', and ≠ means 'not equal to'.

Tip

Memory trick for inequality symbols: The symbol always 'points' to the smaller number, like an arrow. Think of it as a hungry alligator that wants to eat the bigger number!

Worked Example

Problem

Write three different comparison statements using 456,789 and 456,798.

Solution

456,789 < 456,798; 456,798 > 456,789; 456,789 ≠ 456,798

Explanation

Always compare systematically from left to right. Here, 456,798 is greater because it has 9 in the tens place while 456,789 has only 8 in the tens place.

Question

Compare 8,543 and 8,534. Write your answer using < or >.

Hint
Compare digits from left to right until you find a difference.
Show Answer
8,543 > 8,534

Concept

When comparing numbers, start from the leftmost digit and compare place by place until you find a difference.

Show Solution
1

Line up the numbers by place value: 8,543 and 8,534

2

Compare the thousands place: 8 = 8, so move to the next place

3

Compare the hundreds place: 5 = 5, so move to the next place

4

Compare the tens place: 4 > 3, so 8,543 > 8,534

Two numbers aligned vertically by place value: 8,543 on top and 8,534 below. Each digit is in columns labeled Thousands, Hundreds, Tens, Ones from left to right. The tens place digits 4 and 3 are highlighted, with 4 > 3 shown. Final comparison 8,543 > 8,534 written below.

Why?

8,543 > 8,534 because in the tens place, 4 > 3.

Question

Compare 99,999 and 100,000. Which number is greater?

Hint
Remember the rule about numbers with different amounts of digits.
Show Answer
100,000 > 99,999

Concept

When comparing numbers with different amounts of digits, the number with more digits is always greater.

Show Solution
1

Count the digits in each number: 99,999 has 5 digits, 100,000 has 6 digits

2

The number with more digits is always greater

3

Therefore, 100,000 > 99,999

Two numbers shown with digit count: 99,999 labeled as '5 digits' and 100,000 labeled as '6 digits'. An arrow points from 100,000 with text 'MORE DIGITS = GREATER'. Final comparison 100,000 > 99,999 written below.

Why?

100,000 > 99,999 because 100,000 has 6 digits while 99,999 has only 5 digits.

Question

Put these numbers in order from least to greatest: 67,890; 67,098; 67,980

Hint
All numbers have the same digits in the ten-thousands and thousands places, so compare the hundreds place.
Show Answer
67,098 < 67,890 < 67,980

Concept

To order numbers, compare them two at a time, starting with the leftmost digits and working right until you find differences.

Show Solution
1

Line up all three numbers by place value: 67,890; 67,098; 67,980

2

Compare ten-thousands and thousands places: all have 6 and 7, so move to hundreds place

3

Compare hundreds place: 67,098 has 0, 67,890 has 8, 67,980 has 9

4

Order by hundreds place: 0 < 8 < 9, so 67,098 < 67,890 < 67,980

Three numbers aligned vertically by place value: 67,890, 67,098, and 67,980. Columns labeled Ten-thousands, Thousands, Hundreds, Tens, Ones. The hundreds place digits 8, 0, and 9 are highlighted. Below shows the ordering: 67,098 < 67,890 < 67,980 with arrows indicating least to greatest.

Why?

67,098 < 67,890 < 67,980 because when comparing the hundreds place: 0 < 8 < 9.

Question

Write a comparison statement using the = symbol: Compare 45,600 and 45,600.

Hint
When two numbers are exactly the same, we use the equals symbol.
Show Answer
45,600 = 45,600

Concept

When two numbers have exactly the same digits in the same positions, they are equal and we use the = symbol.

Show Solution
1

Compare the two numbers digit by digit: 45,600 and 45,600

2

Ten-thousands: 4 = 4, Thousands: 5 = 5, Hundreds: 6 = 6, Tens: 0 = 0, Ones: 0 = 0

3

Since all digits are identical, 45,600 = 45,600

Two identical numbers 45,600 aligned vertically with place value columns labeled. Each corresponding digit pair (4=4, 5=5, 6=6, 0=0, 0=0) is connected with equal signs. Final statement 45,600 = 45,600 written below with emphasis on the equals symbol.

Why?

45,600 = 45,600 because both numbers are identical in every place value.

Question

Order these four numbers from greatest to least: 234,567; 23,456; 2,345,678; 234,576

Hint
First group by number of digits, then compare within each group.
Show Answer
2,345,678 > 234,576 > 234,567 > 23,456

Concept

To order numbers from greatest to least, first identify which has the most digits, then compare place by place for numbers with the same digit count.

Show Solution
1

Count digits in each number: 2,345,678 (7 digits), 234,567 (6 digits), 23,456 (5 digits), 234,576 (6 digits)

2

The 7-digit number 2,345,678 is greatest

3

Compare the two 6-digit numbers: 234,576 vs 234,567. In the tens place, 7 > 6, so 234,576 > 234,567

4

The 5-digit number 23,456 is smallest

5

Final order: 2,345,678 > 234,576 > 234,567 > 23,456

Four numbers arranged vertically in order from greatest to least: 2,345,678 (labeled '7 digits'), 234,576 (labeled '6 digits'), 234,567 (labeled '6 digits'), and 23,456 (labeled '5 digits'). Greater than symbols (>) connect each number to the next. The tens place digits 7 and 6 in the two 6-digit numbers are highlighted to show the comparison.

Why?

2,345,678 > 234,576 > 234,567 > 23,456 because we order by digit count first, then by place value comparison.