Multiplication of Numbers Basic 3 Mathematics Lesson Note

A. COUNTING SKILL: NUMBERS 771-790, 1-790

Counting from 771 to 790: 771, 772, 773, 774, 775, 776, 777, 778, 779, 780, 781, 782, 783, 784, 785, 786, 787, 788, 789, 790

Counting by 100s from 1-790: 100, 200, 300, 400, 500, 600, 700

Skip counting by 10s from 770-790: 770, 780, 790

Practice counting:

• From 775 to 785: _______
• From 782 to 790: _______
• Backwards from 790 to 780: _______

Fill in missing numbers:

• 776, 777, _____, 779, _____
• 785, _____, 787, _____, 789
• _____, 772, _____, 774, _____

B. WRITING SKILL: WRITING THE NUMBERS

Write in words:

• 771 = Seven hundred and seventy-one
• 775 = Seven hundred and seventy-five
• 780 = Seven hundred and eighty
• 785 = Seven hundred and eighty-five
• 790 = Seven hundred and ninety

Write in figures:

• Seven hundred and seventy-three = _______
• Seven hundred and seventy-eight = _______
• Seven hundred and eighty-two = _______
• Seven hundred and eighty-seven = _______
• Seven hundred and eighty-nine = _______

Practice:

• 774 = _______
• 781 = _______
• Seven hundred and seventy-six = _______
• Seven hundred and eighty-eight = _______

C. MULTIPLICATION OF 2-DIGIT BY 1-DIGIT NUMBERS

What is multiplication? Multiplication is repeated addition. Example: 3 × 4 = 4 + 4 + 4 = 12

Multiplication table review:

• 2 × 3 = 6, 2 × 4 = 8, 2 × 5 = 10
• 3 × 3 = 9, 3 × 4 = 12, 3 × 5 = 15
• 4 × 3 = 12, 4 × 4 = 16, 4 × 5 = 20

Method 1: Without carrying

 23      32      41

×  2    ×  3    ×  2

—-    —-    —-

  46      96      82

Step by step for 23 × 2:

• 3 × 2 = 6 (units)
• 2 × 2 = 4 (tens)
• Answer: 46

Method 2: With carrying

  ¹24      ¹35

×   3    ×   2

—–    —–

   72       70

Step by step for 24 × 3:

• 4 × 3 = 12 (write 2, carry 1)
• 2 × 3 = 6, plus 1 carried = 7
• Answer: 72

Practice multiplication:

1. 12 × 3 = _____
2. 21 × 4 = _____
3. 13 × 2 = _____
4. 32 × 3 = _____
5. 24 × 2 = _____
6. 15 × 4 = _____
7. 26 × 3 = _____
8. 34 × 2 = _____

D. QUANTITATIVE REASONING

Word problems:

1. There are 23 boxes. Each box contains 3 balls. How many balls are there altogether?
2. A farmer plants 14 rows of corn. Each row has 5 corn plants. How many corn plants are there in total?
3. Kemi buys 4 packets of sweets. Each packet has 12 sweets. How many sweets does she have?
4. A classroom has 6 tables. Each table has 4 chairs. How many chairs are there in total?

Number patterns:

1. 12 × 2 = 24, 12 × 3 = _____, 12 × 4 = _____
2. 11 × 2 = 22, 11 × 3 = _____, 11 × 4 = _____
3. 13 × 1 = 13, 13 × 2 = _____, 13 × 3 = _____

Estimation: Round and multiply:

1. 19 × 3 ≈ 20 × 3 = _____
2. 26 × 4 ≈ 30 × 4 = _____
3. 34 × 2 ≈ 30 × 2 = _____

Missing numbers:

1. 15 × _____ = 45
2. _____ × 3 = 72
3. 23 × _____ = 69

Comparison: Which is bigger?

1. 12 × 3 or 13 × 2? _____
2. 15 × 2 or 14 × 3? _____
3. 21 × 3 or 23 × 2? _____

CLASS EXERCISES

1. Count from 778 to 788:
2. Write in words:
   1. 777 = _______
   2. 784 = _______
   3. 790 = _______
3. Write in figures:
   1. Seven hundred and seventy-nine = _______
   2. Seven hundred and eighty-six = _______
4. Multiply:
   1. 12 × 2 = _____
   2. 23 × 3 = _____
   3. 14 × 4 = _____
   4. 31 × 2 = _____
5. Multiply with carrying:
   1. 25 × 3 = _____
   2. 16 × 4 = _____
   3. 27 × 2 = _____
   4. 18 × 3 = _____
6. Word problems:
   1. There are 13 bags. Each bag has 4 oranges. How many oranges are there in total?
   2. A school has 5 classes. Each class has 24 pupils. How many pupils are in the school?
7. Complete the patterns:
   1. 14 × 2 = 28, 14 × 3 = _____, 14 × 4 = _____
   2. 12 × 1 = 12, 12 × 2 = _____, 12 × 3 = _____
8. Find the missing numbers:
   1. 16 × _____ = 48
   2. _____ × 3 = 63
   3. 25 × _____ = 50
9. Estimate by rounding:
   1. 18 × 3 ≈ _____ × 3 = _____
   2. 27 × 2 ≈ _____ × 2 = _____
10. Problem solving: A baker makes 15 cakes each day. How many cakes does he make in 4 days?