Mathematics - Term 1 - Week 3

Addition is the process of combining two or more numbers to find a 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 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: 27 + 46. We can break it down by adding the tens and the units separately. First, add the tens: 20 + 40 = 60. Next, add the units: 7 + 6 = 13. Now, combine the results: 60 + 13 = 73. Therefore, 27 + 46 = 73.

Consider the problem: 85 - 29. We can also break this down. Start with the tens: 80 - 20 = 60. Then, subtract the units: 5 - 9. Since we can't subtract 9 from 5, we need to borrow 1 from the tens, making it 15 - 9 = 6. Now, combine the results: 60 - 6 = 56. Thus, 85 - 29 = 56.

Let's work on these problems as a class. First, try 34 + 58. Break it down into tens and units. Next, solve 72 - 19. Remember to borrow if necessary. After we solve these together, I will ask a few students to explain their thought process and how they arrived at their answers.

Now it's your turn to practice on your own. Solve the following problems: 45 + 37, 90 - 54, 63 + 29, and 100 - 76. Show your working clearly, and once you finish, check your answers with a partner. If you find any mistakes, discuss how you can correct them.

• 42
• 32
• 22
• 52

Answer: 42

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

• 35
• 45
• 55
• 25

Answer: 35

64 minus 29 equals 35 after borrowing from the tens.

Answer: 92

Adding 58 and 34 gives you 92.

Answer: 53

Subtracting 47 from 100 results in 53.

• 42
• 32
• 52
• 22

Answer: 42

23 plus 19 equals 42.

• 54
• 44
• 64
• 74

Answer: 44

80 minus 36 equals 44.

Answer: 90

Adding 72 and 18 gives you 90.

Answer: 33

Subtracting 22 from 55 results in 33.