Mathematics - Term 1 - Week 3

Addition is the process of combining two or more numbers to find their total, while subtraction involves taking one number away from another. To visualize these operations, we can use number lines, counters, or area models. For example, if we have 5 apples and we add 3 more, we can represent this on a number line by starting at 5 and moving 3 steps to the right, landing on 8. Conversely, if we have 8 apples and we subtract 3, we move 3 steps to the left on the number line, landing on 5.

Let's add 47 and 36. We can break this down into tens and units: 40 + 30 = 70 and 7 + 6 = 13. Now, we combine these results: 70 + 13 = 83. Therefore, 47 + 36 = 83. This method helps us see the addition clearly and ensures we don't make mistakes.

Now, let's subtract 58 from 92. We can break it down: 90 - 50 = 40 and 2 - 8 requires borrowing. We can borrow 1 from the 9, making it 8, and the 2 becomes 12. Now, 12 - 8 = 4. So, 92 - 58 = 34. This step-by-step approach helps clarify the process.

Now, let's practice together. Calculate the following: 23 + 19. Start by adding the tens: 20 + 10 = 30, and then the units: 3 + 9 = 12. Combine these results to find the answer. Next, try 75 - 28. Break it down into tens and units, and remember to borrow if necessary. Work through these problems as a class, discussing each step.

Now it's your turn! Solve the following problems on your own: 64 + 29, 150 - 76, 88 + 47, and 92 - 34. Show all your working steps clearly. After you finish, pair up with a partner to review each other's work and discuss any mistakes. Remember, correcting errors is a key part of learning!

• 72
• 82
• 92
• 102

Answer: 82

45 + 37 can be calculated by adding the tens (40 + 30 = 70) and the units (5 + 7 = 12), resulting in 70 + 12 = 82.

• 53
• 63
• 73
• 83

Answer: 53

100 - 47 can be calculated by borrowing: 100 becomes 90, and 10 becomes 10, so 10 - 7 = 3 and 90 - 40 = 50, resulting in 53.

Answer: 95

76 + 19 can be calculated by adding the tens (70 + 10 = 80) and the units (6 + 9 = 15), resulting in 80 + 15 = 95.

Answer: 55

84 - 29 involves borrowing: 84 becomes 74, and 14 - 9 = 5, so 70 - 20 = 50, resulting in 55.

• 82
• 92
• 72
• 64

Answer: 92

58 + 34 can be calculated by adding the tens (50 + 30 = 80) and the units (8 + 4 = 12), resulting in 80 + 12 = 92.

• 45
• 55
• 65
• 75

Answer: 45

120 - 75 can be calculated by borrowing: 120 becomes 110, and 10 - 5 = 5, so 110 - 70 = 40, resulting in 45.

Answer: 85

39 + 46 can be calculated by adding the tens (30 + 40 = 70) and the units (9 + 6 = 15), resulting in 70 + 15 = 85.

Answer: 35

63 - 28 involves borrowing: 63 becomes 53, and 13 - 8 = 5, so 50 - 20 = 30, resulting in 35.