Exam-style question
Try this first
For each value below, state whether it belongs to ℕ and justify your answer: 0, 6, -2 and 3.5.
Model answer
What a good answer should say
- 0 belongs to ℕ because zero is included.
- 6 belongs to ℕ because the set continues through the positive whole numbers.
- -2 does not belong to ℕ because it is negative.
- 3.5 does not belong to ℕ because it is not one of the whole-number values listed in ℕ.
Explanation
Why this works
The set is ℕ = {0, 1, 2, 3, …}. Membership can therefore be checked by considering whether a value is zero or a positive whole number.
Negative values and non-whole values such as 3.5 are not members.
Common mistake
No common mistake is linked to this question yet.