Addition of Whole Numbers – Basic 3 Mathematics Lesson Note (First Term)

A. counting skill: numbers 1-400, 401-700 and 1-700

Counting by 100s: 100, 200, 300, 400, 500, 600, 700

Counting by 50s: 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700

Quick review:

• Count from 395 to 405: _______
• Count from 595 to 605: _______
• Count backwards from 700 to 690: _______

Number patterns:

• 100, 200, 300, _____, _____
• 450, 500, 550, _____, _____
• What comes before 400? _____
• What comes after 699? _____

B. writing skill: writing of numbers

Write in words:

• 234 = Two hundred and thirty-four
• 456 = Four hundred and fifty-six
• 623 = Six hundred and twenty-three
• 700 = Seven hundred

Write in figures:

• Three hundred and forty-five = _______
• Five hundred and sixty-seven = _______
• Six hundred and eighty-nine = _______
• Four hundred and twelve = _______

Practice:

• 389 = _______
• 567 = _______
• Two hundred and ninety-one = _______
• Five hundred and forty-three = _______

C. addition of 2-digit numbers without exchanging

Method: Add units to units, tens to tens

Examples:

 23      45      62

+ 14    + 32    + 27

—-    —-    —-

  37      77      89

Step by step: 23 + 14:

• Units: 3 + 4 = 7
• Tens: 2 + 1 = 3
• Answer: 37

Practice:

1. 32 + 15 = _____
2. 41 + 26 = _____
3. 54 + 23 = _____
4. 61 + 18 = _____
5. 73 + 16 = _____

D. addition of 3-digit numbers with renaming

Method: Add units, tens, hundreds. Carry over when needed.

Example 1 (No renaming):

 234

+ 125

—–

  359

Example 2 (With renaming):

  ¹247

+ 156

—–

  403

Step by step for 247 + 156:

• Units: 7 + 6 = 13 (write 3, carry 1)
• Tens: 4 + 5 + 1 = 10 (write 0, carry 1)
• Hundreds: 2 + 1 + 1 = 4
• Answer: 403

Practice:

1. 234 + 142 = _____
2. 345 + 231 = _____
3. 167 + 258 = _____
4. 289 + 147 = _____
5. 356 + 278 = _____

E. quantitative reasoning

Word problems:

1. A school has 234 boys and 156 girls. How many pupils are in the school altogether?
2. Tolu saved ₦145 in January and ₦267 in February. How much did he save in total?
3. A farmer harvested 289 yams on Monday and 178 yams on Tuesday. What is the total number of yams harvested?

Number puzzles:

1. 234 + _____ = 456
2. _____ + 123 = 345
3. 167 + 258 = _____

Estimation: Round to the nearest 10 and add:

1. 247 + 156 ≈ 250 + 160 = _____
2. 389 + 234 ≈ 390 + 230 = _____

Pattern completion:

1. 123 + 100 = 223, 223 + 100 = _____, _____ + 100 = _____
2. 234 + 111 = 345, 345 + 111 = _____, _____ + 111 = _____

CLASS EXERCISES

1. Count by 100s from 100 to 700:
2. Write in words:
   1. 456 = _______
   2. 623 = _______
3. Write in figures:
   1. Three hundred and seventy-eight = _______
   2. Five hundred and ninety-four = _______
4. Add without renaming:
   1. 32 + 17 = _____
   2. 45 + 23 = _____
   3. 61 + 28 = _____
5. Add with renaming:
   1. 167 + 245 = _____
   2. 289 + 156 = _____
   3. 378 + 247 = _____
6. Word problems:
   1. A shop sold 234 items on Friday and 178 items on Saturday. How many items were sold in total?
   2. Kemi has 156 stickers and Ada has 267 stickers. How many stickers do they have altogether?
7. Fill in the missing numbers:
   1. 145 + _____ = 267
   2. _____ + 189 = 345
8. Round and estimate:
   1. 234 + 167 ≈ _____ + _____ = _____
9. Complete the pattern:
   1. 200 + 100 = 300, 300 + 100 = _____, _____ + 100 = _____
10. Choose the correct answer:
    1. 234 + 156 = (390, 380, 370)
    2. 167 + 258 = (425, 415, 435)