Numbers
Tens and Ones
A number can be made of a single digit, two digits, or more than two digits.
If a number is made of two digits, we group the number in Tens and Ones to make the counting/calculations easier.
Example
Question:Tanmay wants to count all the books on the bookshelf. But it’s difficult for him to count all the books. If there are 94 books on the bookshelf, group them in tens and ones to help him count the books.
Answer: 94 books can be grouped in tens and ones as follows:
Now he can count the number of books as:
So, there are 90 books in 9 groups, adding remaining 4 individual books it will give:
90 books and 4 books = 94 books
Tens and Ones as Place Value:
- When we have more than 9 items, write them in two columns ‘Tens’ and ‘Ones’.
- In the Tens column we write down how many "tens" we have, followed by the remaining items in the ones column.
- A ‘Ten’ indicates bundle or group of 10 individuals or singles.
- 1 Object = 1 Ones
- 10 Ones = 1 Ten
- If there is a group of 10 Tens, we call it Hundreds.
- 10 Tens = 1 Hundred
Order of place value (Once, Tens & Hundreds)
Ones, Tens and Hundreds from right to left are written as follows.
• Place value of One-digit numbers
- All One-digit numbers are smaller than 10. A single digit number cannot make a group of 10.
• Place value of Two-digit numbers
- The number 10 is the first and the smallest two-digit number.
Let’s take 10 pencils.
Now make a group of 10 pencils.
- We can make only 1 group. It represents 1 Ten. But there is no single pencil remaining. It indicates 0 ones.
- So, the number 10 can write as:
Similarly, we can write representation of the all two-digits numbers.
Example
- If we take 21 pencils, we can make 2 groups of 10 pencils that can be represented as 2 Tens.
- 1 remaining pencil can be represented as 1 Ones.
- We can write 21 as:
2 Tens and 1 Ones = 21
• Place value of 100
We can represent 100 as 10 groups of Tens.
We cannot write 100 as:
We use the hundreds place. The number 100 is written as:
100 is the first and smallest three-digit number.
Misconception:
Do not write the numbers at the place value table from the left. If we have to write the numbers 7, 12 and 70. Don’t write as:
The correct way is: Always write the numbers from right to left.