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How to Add Decimals? Definition & Examples

May 23, 2022

In this article, we will read about Add decimals and their applications. But first, let’s learn about Decimal. 

Suppose you have visited shopping malls, fuel stations, electricity stations, railway stations, etc. In that case, you may have seen the cost mentioned on your purchase bills. Do you ever notice that there is a dot between the values in the price you pay?

Have you ever wondered what that dot means? How does it differ from the value of the number? In Algebra (the branch of Mathematics), this dot is a Decimal. It plays a significant role in the number system.

What Is Decimal?

A decimal is a fraction whose denominator is the power of 10, i.e., 10, 100, 1000, and many more. It is denoted by the ‘dot (.)’ between numbers. The dot in a decimal number is called a decimal point, while the digits following the decimal point are smaller than one.

For example, the number 345.808 is a decimal number.


Here, 345 is the part of a whole number, and 808 is a fractional or decimal part below that 1 in value.

If we move from left to right places in a decimal number, the decimal place value determines the tenth, hundredth, thousandth, and so on places. Tenth place means 1/10 or 0.1 in decimal form. At the same time, a hundredth place means 1/100 or 0.01 in decimal form.

We can differentiate the decimal values with the help of a place value chart.


We can also represent decimal numbers on number lines. On the number line, decimal numbers lie between two continuous integers. We can write decimal numbers both in expanded form and in words.

For example,


12.456 can be written as

In expanded form:- 10 + 2 + 4/10 + 5/100 + 6/1000

In words:- Twelve and four hundred fifty-six thousandth

Some more Examples of Decimals

Here are some examples of decimals that will help you learn more about them.

Example 1: Write the following as decimals:

Hundreds (100)Tens (10)Ones (1)Tenth (110)

Solution: The decimal form of the given numbers are:

(i) 538.1

(ii) 273.4

(iii) 354.6

Example 2: Write the short form of the following numbers:

(i) 20 + 3 + 5/10

(ii) 4 + 3/10 + 7/100 + 1/1000

Solution: The short form of the given numbers is as follows:

(i) 23.5

(ii) 4.371

Arithmetic Operations on Decimals

Decimal numbers can perform arithmetic operations like addition, subtraction, multiplication, and division like other number systems. Let’s have a look at how to add and subtract decimals.

Addition Operation on Decimals

Adding two or more decimal numbers is called adding decimals. However, there are certain rules to follow when you add decimals. Let’s learn more about how to add decimals, the rules to add decimals, and some examples.

How to Add Decimals?

A decimal number has a whole number part, a decimal point, and a fractional part. If you want to add decimals, aligning each digit according to its place value one below another is necessary. You can use a place value chart, as described above, to add decimals. The values to the left of the decimal points are called ones, tens, and hundreds, while those to the right side of the decimal point are called tenth, hundredth, thousandth, and so on.

Rules to Add Decimals

The following given are some rules that help you with learning how to add decimals:

  1. Place the digits in decimal numbers according to the place value chart below each other.
  2. Whenever needed, convert decimal numbers into like decimals.
  3. You can add zeros to cover up the length of short decimal numbers.
  4. Add the numbers and the decimal point at its place in the last place.
  5. In cases where the sum of two tenth place values is more than 9, we will perform the addition similar to additions with carrying numbers.

Some Examples to Understand How do you Add Decimals

Here are some examples that can help you understand how to add decimals in different situations. Let’s have a look.

Example 1: Find the sum of 0.29 + 0.36.


We can place these digits in place value chart as follows:

Ones (1)Tenth (110)Hundredth (1100)

The sum of these digits is given as


Therefore, the sum of 0.29 and 0.36 is 0.65.

Example 2: Add decimal numbers 20.62 and 13.02.

Solution: Arrange these digits according to their place values below each other.

 2 0 . 6 2 + 1 3 . 0 2 = 3 3 . 6 4

Therefore, the sum of the given decimal numbers is 33.64.

How to Add Decimals and Whole Numbers?

Adding decimals and whole numbers is similar to adding two or more decimal numbers. You need to follow a step more before adding a decimal number and a whole number. Add a decimal point to the whole number and then add zeros to make the length of the whole number equal to the decimal number.

Let us take some examples to learn more about how to add decimals with whole numbers.

Example 1: Add 3.25, 0.075, and 5.


Add these numbers, but the place values of each digit below each other, and then add the required number of zeros to the numbers.

                         3 . 2 5 + 0 . 0 75 + 5 . 0 0 0 =  8 . 3 2 5

Therefore, the sum of given numbers is 8.325.

Example 2: What will be the sum of 105 and 1.108?


To add these numbers, put them according to their place values below each other and add zeros to the required places.

                         1 0 5 . 0 00 +  0 0 1 . 1 0 8 = 1 0 6 . 1 0 8

Therefore, the sum of the given numbers is 106.108.

Subtraction Operation on Decimals

Like the addition operation, subtraction of decimals is done by placing digits according to their place values below each other. After that, you can perform the subtraction operation on the decimal numbers. In cases where you need to borrow numbers, it will similarly operate as in simple subtraction of numbers.

Let us understand how to subtract decimals with the help of some examples.

Example 1: Subtract 2.051 km from 5.206.

Solution: To subtract the given decimal numbers, put each digit according to their place value below each other.

                          5 . 2 0 6 – 2 . 0 5 1 = 3 . 1 5 5

Therefore, after subtracting the given numbers, we get 3.155 km.

Example 2: What is 7.368 – 1.15?

Solution: After placing each digit according to their place values below each other,

we get

                          7 . 3 6 8 – 1 . 1 5 0 = 6 . 2 1 8

Therefore, 7.368 – 1.15 = 6.218.

How to Add Decimal in Excel?

Excel is an excellent tool for calculating various arithmetic operations on numbers. You can add, subtract, multiply, or divide numbers very efficiently with the help of Excel.

To learn how to add decimal numbers in excel, you need to follow the given steps:

Step 1: Open the new or existing workbook in Excel.

Step 2: Select the column you want to perform the addition operation on decimals.

Step 3: Click the right button and select the ‘Format Cells’ option.

Step 4: Select the category of your numbers under the ‘Number’ tab.

Step 5: Set the decimal place up to 2

Step 6: Click on the ‘OK’ option.

In this way, you can add decimal numbers in excel.

Worksheet on Decimals

Here are some questions to try to practice decimals and their operations.

Q1. Find the value of:

(i) 11.6 – 9.847

(ii) 27.076 + 0.55 + 0.004

Q2. Naresh walked 5 km 37 m in the morning and 2 km 9 m in the evening. How much distance did he walk in all? (Hint: 1 km = 1000 m)

Q3. Tina had 40 m 5 cm long cloth. She cuts 5 m 70 cm length of cloth from this for making a curtain. How long is the piece of cloth left with her? (Hint: 1 m = 100 cm)

Q4. Ravi purchased 6 kg 500 g rice, 3 kg 10 g sugar, and 20 kg 900g flour. Could you find the total weight of his purchases? (Hint: 1 kg = 1000g)

Q5. Aakash bought vegetables weighing 15 kg. 2 kg 700 g were onions, 4 kg 50 g were tomatoes, and the rest were potatoes. What is the weight of the potatoes?

Frequently Asked Questions

1. How do you add two decimals?

Ans. To add two decimals, you simply add the digits in the same place value.For example, to add 3.9 and 8.7, we start by adding the ones place (3 + 8 = 11). Then we move on to the tens place (9 + 7 = 16), then hundreds place (4 + 1 = 5). We’ll get a total of 26!

2. How do we add and subtract decimals?

Ans. To add decimals, just like you would with whole numbers. Simply place them side by side and add the values.Let’s say you want to add 0.5 + 1.3. That would look like this: 0.5 + 1.3 = 1.8 To subtract decimals, subtract the numbers in the number place first, then move to the right and subtract from each other. If you need to borrow from a higher place value, do so by putting an extra zero before adding it on, then carry out that step before moving on to the next step. For example -4.5 – 1.4 = -5.9

3. How do you add three decimals?

Ans. To add three decimals, you need to add the three numbers together and then count how many digits are in the result. Then, you need to count number of digits and how many digits there are in each number you added together. For example, if we had 1.1 + 2.2 + 3.3 = 6.6 and we counted that there were two digits in 6.6, then we would write down the sum as 2.6

4. How to Add Decimals and Fractions?

Ans. Decimals and fractions are two different ways of representing numbers, but they can be added together. Converting the numbers to a common denominator is the first step. If they share the same denominator, then you can add them without converting them. If not, then you will need to convert both of them so that they do have a common denominator.

5. What are the Steps for Adding Decimals?

Ans. Adding decimals and fractions is a lot like adding whole numbers. For example, if we want to add 5.6 and 2.3, we can do it in the same way we would add any two whole numbers 5.6 + 2.3 = 7.9

add decimals


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