Number Sense (2 digit numbers)

Number Sense (2 digit numbers) - Class 1

  • Number Sense
  • Place Value
  • Number Name
  • Number Sense

    Number sense is understanding and playing with numbers in a way that makes math easier and more fun. With an understanding of number sense, you will be able to tackle any math challenges that come your way.

    Number sense helps you do everyday things. When you count how many cookies you have left, or figure out how much time you have until your favorite TV show starts, you're using number sense. To navigate the world of numbers, it functions similarly to your math radar. Now, in this article, we will learn about numbers, one-digit numbers, two-digit numbers, forward counting, backward counting, and place value.


    A number is a mathematical quantity used to represent values and perform calculations. Digits are used to symbolize these numbers, which are in the form of symbols ranging from 0 to 9. Numbers play a fundamental role in mathematics and everyday life.

    Numbers 1 to 10 - CREST Olympiads


    The number zero is very special in mathematics. A valueless number is zero and it means emptiness.

    Zero Number - CREST Olympiads

    For example: The image below shows a plate with four apples.
    Now, if you remove the four apples, the plate contains 0 apple.

    Example of Zero - CREST Olympiads

    One-digit number

    One-digit numbers are formed by using single digits, ranging from 0 to 9.

    Example of one digit number - CREST Olympiads

    Two-digit numbers

    Combining digits 0 to 9 produces numbers with two digits or more. They can represent numbers from 10 to 99.

    Example of two-digit numbers
    Smallest and Largest two-digit number - CREST Olympiads

    Forward Counting

    Forward counting is the process of adding one to a number to get the next number in a sequence. It is the process of increasing numbers in a sequential order.

    Example of Forward Counting - CREST Olympiads

    Read About: Addition

    Backward Counting

    Backward counting is when you start with a number and then decrease it step by step, moving in the opposite direction of counting forward. It is the process of subtracting one from the number to find the number that comes before it.

    Example of Backward counting - CREST Olympiads

    Before Number

    The before number means the number that comes to the left of the given number.
    The difference between both numbers is one.

    Example of before number - CREST Olympiads

    In between Number

    A number that lies between or in the middle of the two numbers.

    Example of in-between number - CREST Olympiads

    After Number

    The after number means the number that comes right after the given number.

    This number exceeds the given number by one.

    Numbers that come after are always greater than the given number.

    Example of After Number - CREST Olympiads

     Read More: Number Sense (3-Digit Numbers)

    Missing Number

    Missing numbers are the numbers that have been missed in the given series of numbers with similar patterns among them.

    For Example: Find the missing number 3, 6, 9, __, 15, 18;

    Missing Number - CREST Olympiads

    In this given series, we can see:

    3 + 3 = 6; 6 + 3 = 9; 15 + 3 = 18

    Here, If we add 3 to a previous number, we will get the next number in the given series.

    So, 9 + 3 = 12.

    Hence, the required number is 12.

    Skip Counting

    Skip counting is the process of counting by skipping through a particular number of places in the counting sequence.

    The same count must be done each time to skip count.

    Example: Skip counting of 2: 2, 4, 6, 8, 10 etc

    Example of Skip Counting - CREST Olympiads

    Place Value

    Place value is the value of each digit in a number.

    The place value of the tens digit for a two-digit number equals 10 times the value of the digit.

    Place Value of two digit number - CREST Olympiads

    Here, 7 is at the tenth place ;So, the place value of 7 is 7 x 10 = 70 while 4 is at the ones place,so its place value is 4 x 1 = 4 ;

    Hence , the number is 70 + 4 = 74.

    Example of Place Value - CREST Olympiads

    Here, 5 is at ones place, while 9 is at tens place.

    Number Name

    To uniquely identify each number, we simply give it a name, which is known as a "number name."

    All the numbers from 1 to 100 in words are as follows:

    Number Names for 1 to 100 - CREST Olympiads

    Share Your Feedback

    CREST Olympiads has launched this initiative to provide free reading and practice material. In order to make this content more useful, we solicit your feedback.

    Do share improvements at Please mention the URL of the page and topic name with improvements needed. You may include screenshots, URLs of other sites, etc. which can help our Subject Experts to understand your suggestions easily.

    Maths Related Topics for Class 1