IndianTechnoEra: Ordering Two-Digit Numbers

Ordering Two-Digit Numbers

We have learned how to compare two-digit numbers. Now we can use that skill to arrange numbers in the correct order.

Numbers can be arranged from smallest to largest or from largest to smallest.

Learning Objectives

• Understand number order.
• Arrange two-digit numbers from smallest to largest.
• Arrange two-digit numbers from largest to smallest.
• Use tens and ones to decide the correct order.
• Find the smallest and largest number in a group.

What Is Number Order?

Number order means arranging numbers in a particular sequence.

When numbers are arranged from small to big, we call it ascending order.

When numbers are arranged from big to small, we call it descending order.

Smallest to Largest

To arrange numbers from smallest to largest, start with the smallest number and move toward the largest number.

Arrange 23, 15 and 31.

15 < 23 < 31

So the order is:

15, 23, 31

Largest to Smallest

To arrange numbers from largest to smallest, start with the largest number and move toward the smallest number.

Arrange 23, 15 and 31.

31 > 23 > 15

So the order is:

31, 23, 15

Using Tens to Order Numbers

When ordering two-digit numbers, first look at the tens digits.

Consider 24, 51 and 37.

24 has 2 tens.
37 has 3 tens.
51 has 5 tens.

24 < 37 < 51

When the Tens Are the Same

If two numbers have the same tens digit, compare their ones digits.

Arrange 42, 47 and 45.

All three numbers have 4 tens.
Compare the ones: 2, 7 and 5.

42 < 45 < 47

Finding the Smallest Number

To find the smallest number, compare the numbers and choose the one with the smaller value.

Find the smallest number: 35, 18, 42

Smallest = 18

Finding the Largest Number

To find the largest number, compare the numbers and choose the one with the greatest value.

Find the largest number: 35, 18, 42

Largest = 42

Ordering Several Numbers

When there are several numbers, compare them carefully and arrange them one by one.

Arrange 34, 21, 45 and 12 from smallest to largest.

12, 21, 34, 45

From largest to smallest:

45, 34, 21, 12

Common Mistakes

• Mixing up ascending and descending order.
• Comparing only the ones digits.
• Ignoring the tens digit.
• Putting a larger number before a smaller number in ascending order.

Practice

1. Arrange 24, 12 and 31 from smallest to largest.

2. Arrange 45, 27 and 39 from largest to smallest.

3. Find the smallest number: 56, 42, 63.

4. Find the largest number: 28, 51, 46.

5. Arrange 43, 41 and 48 from smallest to largest.

Try It Yourself

Write five two-digit numbers around you or choose five numbers randomly. Arrange them first from smallest to largest and then from largest to smallest.

Smallest → Largest
Largest → Smallest

Quick Revision

• Ascending order means smallest to largest.
• Descending order means largest to smallest.
• Compare tens first.
• If tens are equal, compare ones.
• Use comparison skills to arrange numbers correctly.

Chapter 2 Complete

You have now learned how two-digit numbers are made using tens and ones, how to read them, compare them and arrange them in order.

These ideas will help you understand addition, subtraction and other number concepts in the chapters that follow.