Mathematics - Term 2 - Week 9

Number sense is the ability to understand, relate, and connect numbers. It involves recognizing numbers in different forms, such as whole numbers, fractions, and decimals. In this lesson, we will explore how to count in various ways, including skip counting and counting backwards. We will also discuss the importance of understanding the value of numbers in different contexts.

Let's look at skip counting by 5s. If we start at 0, the sequence goes: 0, 5, 10, 15, 20, and so on. Notice how each number increases by 5. To visualize this, we can use a number line. Mark the points at 0, 5, 10, 15, and 20. This helps us see the pattern clearly and understand how skip counting works.

Now, let's practice counting backwards from 20 to 0. I will say a number, and you will tell me the next number in the sequence. For example, if I say 20, you will say 19. Let's start: 20, ___? (19) Next: 19, ___? (18) Continue this until we reach 0. This exercise helps us understand subtraction and the relationship between numbers.

Now it's your turn to solve some problems on your own. Here are a few questions: 1) What is the next number in the sequence: 10, 15, 20, ___? 2) Count backwards from 30 to 0 and write down the numbers you say. 3) Solve: 25 - 7 = ___. Remember to show your working clearly. After you finish, we will review your answers together.

• 20
• 25
• 30
• 35

Answer: 20

The sequence increases by 5 each time, so after 15 comes 20.

• 0, 1, 2, 3
• 10, 9, 8, 7
• 5, 10, 15
• 1, 2, 3, 4

Answer: 10, 9, 8, 7

Counting backwards means decreasing the numbers, as shown in this sequence.

Answer: 18

Subtracting 12 from 30 gives us 18.

• 8
• 10
• 12
• 14

Answer: 8

The sequence is 0, 2, 4, 6, 8, so the 5th number is 8.

Answer: 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0

These are the numbers counted backwards from 15 to 0.

• 30
• 35
• 40
• 45

Answer: 40

Adding 25 and 15 gives us 40.

• 6
• 7
• 8
• 9

Answer: 7

The sequence increases by 2 each time, so after 5 comes 7.

Answer: 15

Subtracting 5 from 20 leaves you with 15 apples.