Introduction

21 is written as “Twenty-One”. Now, we will try to understand its significance with the help of an example. Suppose we bought 1 kg Onion for Rs 21, then we say that “I bought 1kg Onion for Twenty-One Rupees. This article will help you understand how to write 21 in words using English alphabets.

Place Value Chart for 21

21 is a 2-digit number. The place value chart of 21 is as follows:

We can see that there is 1 in the one's place and 2 in the tens place.

How to Write 21 in Words?

The place value system as we use today, is a derived version of the Place value numbering system invented in India. After the invention of zero, it made the place value system more effective to use. Starting from a unit place (right side), we keep going towards the left. But while naming the numbers, we read them from right to left, as mentioned in the above chart. So, while converting a two-digit number in words, we use the tens digit as twenty, thirty, forty, and so on. And, this is followed by the unit digit number. Hence, the number 21 is read as, “Twenty-One”.

Expanded form of 21

The expanded form of 21 is as follows:

\begin{aligned}

&2 \times \text { Ten }+1 \times \text { One } \\

&=2 \times 10+1 \times 1 \\

&=20+1 \\

&=21 \\

&=\text { Twenty One }

\end{aligned}

Important Points About 21

• 21 is a natural number which is succeeded by 20 and preceded by 22.

• 21 is an odd number because it leaves a remainder ‘1’ when divided by 2.

• The numbers which leave a remainder ‘1’ when divided by 2 are odd numbers.

• 21 is a composite number because it has 1, 3, 7, and 21 as its factors.

• Square root of 21 is 4.58, hence it is not a perfect square.

• The cube root of 21 is 2.75, hence it is not a perfect cube.

• In roman numerals 21 is written as XXI

You can find out the detailed other number in words article list below:-