Lesson 1 – Addition

Objective:
At the end of this lesson, students should be able to add several two, three and four digit numbers together.
Addition is done using the plus (+) sign. The answer we get by adding two numbers is called the sum.

Example 1
 H T U
3  4 5
+5  3 4
  8  7 9
Start adding from the right side. You add units to units, tens to tens and hundreds to hundreds.
5 units + 4 units = 9 units
4 tens + 3 tens = 7 tens
3 hundreds + 5 hundreds = 8 hundreds.
Write all your answers under the appropriate columns.

Example 2

6 and 5 units equals 11 units. 11 units make 1 ten and 1 unit. Write 1 under the units column and carry 1 ten to the tens column. 1+ 8 + 3 tens make 12 tens. 12 tens make 1 hundred and 2 tens. Write 2 under the tens column and carry 1 hundred.
1 + 9 + 4 make 14 hundreds. 14 hundreds make 1 thousand and 4 hundreds. Write 4 under hundreds column and 1 under the thousands column. Your answer becomes 1421.

Example 3
4121 + 580 + 246