Ordering 2-Digit Numbers
Ordering two-digit numbers means putting them in a line from smallest to biggest (ascending) or biggest to smallest (descending).
We use the same trick as comparing: look at the tens digit first, then the ones digit.
What is Ordering 2-Digit Numbers - Class 1 Maths (Numbers up to 100)?
Ascending order: Numbers go from the smallest to the biggest (climbing up).
Descending order: Numbers go from the biggest to the smallest (coming down).
To order two-digit numbers, first group them by their tens digit, then sort within each group by the ones digit.
Solved Examples
Example 1: Ascending Order
Question: Arrange 45, 23, 67 in ascending order.
Think:
- Compare tens: 2, 4, 6
- Smallest tens = 2 → 23 first
- Next = 4 → 45
- Biggest = 6 → 67 last
Answer: 23, 45, 67 (ascending).
Example 2: Descending Order
Question: Arrange 81, 18, 55 in descending order.
Think:
- Compare tens: 8, 1, 5
- Biggest = 8 → 81 first
- Next = 5 → 55
- Smallest = 1 → 18 last
Answer: 81, 55, 18 (descending).
Example 3: Same Tens Digit
Question: Arrange 34, 31, 37 in ascending order.
Think:
- All have tens = 3 (same)
- Compare ones: 4, 1, 7
- Smallest ones = 1 → 31
- Next = 4 → 34
- Biggest = 7 → 37
Answer: 31, 34, 37.
Example 4: Ria's Test Marks
Question: Ria scored 78 in Maths, 65 in Hindi, and 82 in Science. Arrange from highest to lowest.
Think:
- Compare: 82 > 78 > 65
Answer: 82, 78, 65 (descending).
Example 5: Find the Smallest
Question: Which is the smallest: 49, 94, 44?
Think:
- Tens: 4, 9, 4
- 49 and 44 both have tens = 4; compare ones: 9 vs 4
- 44 < 49, and both < 94
Answer: 44 is the smallest.
Example 6: Find the Biggest
Question: Which is the biggest: 56, 65, 55?
Think:
- 65 has tens = 6 (biggest tens digit)
- 56 and 55 have tens = 5
Answer: 65 is the biggest.
Example 7: Order Four Numbers
Question: Arrange 72, 27, 70, 77 in ascending order.
Think:
- 27 (tens=2) is smallest
- 70, 72, 77 all have tens=7; sort by ones: 0, 2, 7
Answer: 27, 70, 72, 77.
Key Points to Remember
- Ascending = smallest to biggest. Descending = biggest to smallest.
- Compare tens digits first. More tens = bigger number.
- If tens are the same, compare ones digits.
- When ordering many numbers, find the smallest (or biggest) first, then the next, and repeat.
- A number chart (1–100) makes ordering easy — numbers increase as you move right and down.
Practice Problems
- Arrange 88, 38, 58 in ascending order.
- Arrange 91, 19, 50 in descending order.
- Which is the smallest: 46, 64, 44?
- Arrange Dev's, Neha's, and Arjun's heights: 42 cm, 48 cm, 45 cm (shortest to tallest).
- Write 5 two-digit numbers and arrange them from biggest to smallest.
- Arrange: 73, 37, 33, 77 in ascending order.
Frequently Asked Questions
Q1. How do I order two-digit numbers?
Look at the tens digit first. The number with the smallest tens digit comes first in ascending order. If tens are the same, compare the ones digit.
Q2. What is the difference between ascending and descending?
Ascending goes from smallest to biggest (like climbing up). Descending goes from biggest to smallest (like going down).
Q3. How do I order numbers when some have the same tens digit?
When tens are equal, compare the ones digits. For example, 42 and 47 both have 4 tens, but 42 < 47 because 2 < 7.
Q4. What is the smallest two-digit number?
10 is the smallest two-digit number. It has 1 ten and 0 ones.
Q5. What is the largest two-digit number?
99 is the largest two-digit number. It has 9 tens and 9 ones.
Q6. Can I use a number chart to help with ordering?
Yes. On a 1-to-100 chart, numbers increase as you go right and down. This makes it easy to see which number is bigger or smaller.
