1 1

5387     → Sum

The resulting number is called the sum. 2 or more than 2 numbers to be added are called addenda (plural form of addendum). Here 2438 and 2949 are addenda.

Addition of five-digit and six digit numbers:

We know how to add three-digit and four digit numbers. Now, we will learn to add larger numbers.

Consider the following examples:

1. Find the sum of 43428 and 46325.

Arrange the digits of the addenda in columns and add as usual.

1

89753  → Sum

The sum is 89753.

2. Find the sum of 58209 and 23490.

Arrange the digits of the addenda in columns and add as usual.

1

81699  → Sum

The sum is 81699.

3. Find the sum of 569438 and 234526.

Arrange the digits of the addenda in columns and add as usual.

11   1

803964                → Sum

The sum is 803964.

4. Find the sum of 669702, 154789 and 113465.

Arrange the digits of the addenda in columns and add as usual.

1

937956               → Sum

The sum is 937956.

We can add two numbers in any order. The sum remains the same. This property is also called commutative property.

For example:

Find the sum of 460721 and 237544.

Solution:

 460721 +237544   698265 Or 237544 +460721   698265

In both cases, the sum remains the same.

If zero is added to a number, the sum is the number itself. Zero is called additive identity.

For example:

Solution:

423456

+        0

423456

The sum is the number itself.

While adding three or more numbers we may group the numbers in any order. The

Sum remains the same. This is also called grouping property of addition.

For example:

Solution:

 First method   214061 +142131   356192     356192 +234250   590442 Second method   142131 +234250    376381     376381 +214061   590442

We see that (214061 + 142131) + 234250 = (142131 + 234250) + 214061.

1. Ron earns $27425 per month and Sam earns$24639 per month. How much do they earn per month together?

Solution:

Ron earns per month                       =   $27425 Sam earns per month = +$24639

They earns per month                     =    $52064 So, their total earnings per month =$52064

2. Jack has $14321, David has$21109 and John has $30201. How much money do they have together? Solution: Jack has =$14321

David has          =    $21109 John has = +$30201

Total amount     =    $65631 So, the amount they have together =$65631