Lesson 1- Addition

Objective:

At the end of the lesson, students should be able to add several two and three digit numbers together.

Addition is done using the plus (+) sign. The answer we get by adding two numbers is called the SUM.

Example 1

Add 83 to 21

Start adding from the right side. 3 and 1 units are 4 units. 8 and 2 tens make 10 tens. We have 10 tens and 4 units that is 104.

Example 2

Start your addition from the right side. 4 and 7 units make 11 units which is 1 Ten 1 unit. Write 1 and carry 1 to the Tens column. 1 + 5 + 4 Tens make 10 Tens which is 1 Hundred. Write 0 and carry 1 to the Hundreds column. 1 + 8 + 1 Hundreds will be 10 Hundreds which is 1 Thousand. So you write 10. Your answer now becomes 1001.

Example 3

361 + 245 + 29

This can be arranged vertically as

1 + 5 + 9 units make 15 units which is 1 Ten and 5 units. Write 5 in the units column. Carry 1 Ten to the Tens column. 1 + 6 + 4 + 2 make 13 Tens which is 1 Hundred and 3 Tens. Write 3 in the Tens column and carry 1 Hundred to the Hundreds column. 1 + 3 + 2 Hundreds make 6 Hundreds. Write 6 in the Hundreds column. The answer becomes 635.

Example 4