Mathematics - Term 3 - Week 9

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 drawings. For example, if we have 5 apples and 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 subtract 3, we move 3 steps to the left, landing on 5.

Let's solve 27 + 45. We can break this down by adding the tens and the units separately. First, add the tens: 20 + 40 = 60. Then, add the units: 7 + 5 = 12. Now, combine these results: 60 + 12 = 72. Therefore, 27 + 45 = 72.

Now, let's look at 82 - 37. Again, we can separate the tens and units. Start with the tens: 80 - 30 = 50. Next, subtract the units: 2 - 7. Since we can't subtract 7 from 2, we need to borrow 1 from the tens, making it 12 - 7 = 5. Now combine the results: 50 + 5 = 55. Thus, 82 - 37 = 55.

Now it's your turn to try some problems with guidance. Let's solve 34 + 29 together. First, add the tens: 30 + 20 = 50. Then, add the units: 4 + 9 = 13. Combine these: 50 + 13 = 63. Now, try 56 - 19. Start with the tens: 50 - 10 = 40. For the units: 6 - 9, we need to borrow, making it 16 - 9 = 7. Combine: 40 + 7 = 47. Discuss your answers with a partner.

Now, complete the following problems on your own: 1) 45 + 36 2) 78 - 24 3) 63 + 19 4) 90 - 45. Show all your working clearly. After finishing, exchange your work with a partner to check for accuracy and discuss any mistakes.

• 42
• 32
• 22
• 52

Answer: 42

15 + 27 equals 42 when you add the two numbers together.

• 35
• 45
• 55
• 25

Answer: 35

64 - 29 equals 35 after performing the subtraction.

Answer: 101

82 + 19 equals 101 when you add the two numbers.

Answer: 27

50 - 23 equals 27 after performing the subtraction.

• 70
• 80
• 90
• 100

Answer: 80

33 + 47 equals 80 when you add the two numbers.

• 35
• 45
• 55
• 65

Answer: 35

91 - 56 equals 35 after performing the subtraction.

Answer: 100

74 + 26 equals 100 when you add the two numbers.

Answer: 63

100 - 37 equals 63 after performing the subtraction.