3rd Class Mathematics Addition Addition

Learning Objectives

This lesson will help you to:

• Understand the concept of addition using a 10 x 10 grid.
• Add using 2 digit numbers.
• Add using 3 digit numbers.
• Apply addition to real life situations.

Real Life Examples

• Addition helps in calculating the money spent for buying commodities from the market.
• Addition helps in calculating measurements like distance

AMAZING FACTS

• The opposite sides of a dice always add up to seven.

Quick concept Review

Addition is combining smaller sets to a bigger single set. Facts of daily life help us in understanding the concept better.

More about Addition

Addition is one of the basic four operations.

• It is denoted by the symbol"+". For example: 4 added to 9 can be written as 9 + 4.
• The numbers that are added are called addends.
• A 10 x 10 number grid is a helpful tool to add 2-digit numbers.
• Some words that denote addition are "in all", "total", "sum" and "altogether".
• Addition can be done in different ways s

        Counting in tens: 55 + 23 = 55 + 10 + 10 + 3 = 75 + 3 = 78

• To make addition easier it is important to regroup the numbers.

        For example: 421 + 379

Add the ones = 1 + 9 = 10

Add the tens = 20 + 70 + 10 = 100

Add the hundreds = 400 + 300 + 100 = 800

Add 800 + 100 + 10 = 910

Similarly for four digit numbers first of all add one digits, then tens, then hundreds and then thousands respectively.

PROPERTIES OF ADDITION

1. Commutative or Order Property of Addition: Two or more than two numbers can be added in any order

e.g.

• 290 is same as 1290 + 2130.

2. Associative property of addition: Sum of three or more number is not affected by their grouping e.g.

1200 + 1400 + 1300 = (1200 + 1400) + 1300 or 1200 + (1400 + 1300).

3. Sum of zero (0) and number is the number itself. This zero is called identity element e.g. 7000 + 0 = 0 + 7000 = 7000.

HISTORICAL PREVIEW

• The ‘+’ and ‘-‘symbols first appeared in print in mercantile arithmetic published in Leipzig in 1489.