Mathematics - Term 4 - Week 7

Addition is the process of finding the total or sum by combining two or more numbers. Subtraction, on the other hand, involves taking one number away from another to find the difference. To visualize these operations, we can use number lines, counters, or drawings. 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 give away 3, we can move 3 steps to the left on the number line to find that we have 5 apples left.

Let's solve the problem: 23 + 17. We can break this down by adding the tens and the units separately. First, add the tens: 20 + 10 = 30. Next, add the units: 3 + 7 = 10. Now, combine these results: 30 + 10 = 40. Therefore, 23 + 17 = 40.

Now, let's look at a subtraction problem: 45 - 19. We can also break this down. Start with the tens: 40 - 10 = 30. Then, subtract the units: 5 - 9. Since we can't take 9 from 5, we need to borrow 1 from the 30, making it 4. Now we have 15 - 9 = 6. Finally, combine the results: 30 - 6 = 26. Thus, 45 - 19 = 26.

Let's work through some problems together. First, try adding 34 + 29. Break it down by adding the tens and units. Next, for subtraction, solve 56 - 23. Remember to borrow if necessary. Discuss your strategies with a partner and share how you visualized the problems.

Now it's your turn! Solve the following problems on your own: 1) 67 + 28, 2) 84 - 37, 3) 15 + 46, 4) 92 - 54. Show all your working steps clearly. After completing the problems, review your answers and check for any mistakes. If you find any, think about what strategy you could use to correct them.

• 77
• 67
• 87
• 75

Answer: 77

When you add 45 and 32, you get 77.

• 39
• 49
• 29
• 41

Answer: 39

Subtracting 19 from 58 gives you 39.

Answer: 90

Adding 72 and 18 results in 90.

Answer: 55

Subtracting 45 from 100 leaves you with 55.

• 53
• 63
• 73
• 83

Answer: 63

34 plus 29 equals 63.

• 53
• 63
• 73
• 83

Answer: 53

Subtracting 37 from 90 results in 53.

Answer: 100

Adding 25 and 75 gives you a total of 100.

Answer: 38

Subtracting 22 from 60 results in 38.