Sets

Question 1

What does Q stand for in mathematics?

Answer 1

Q - Is a rational number,
- Rational numbers are numbers that can be written as fractions
- And that are divisible by sqrt

Question 2

What does XER mean?

Answer 2

x is a real number belonging to the set of real numbers

Question 3

What does R stand for in mathematics?

Answer 3

R - Is a real number
- Real Numbers are combinations of irrational and rational numbers.
- They consist of: Natural numbers, fractions and decimals
- They can be both positive and negative
- All arithmetic can be applied to real numbers. if it cant then it is not a real number.
-

Question 4

What is the difference between Natural Numbers and Whole numbers.

Answer 4

Natural numbers don’t contain while Whole numbers do

Question 5

What are Irrational numbers?

Answer 5

Numbers that aren’t perfect squares or perfect cubes etc.
e.g. sqrt(25) is a rational number as it is equal to 5]
sqrt(26) is not a rational number though as it does not have a whole number answer/isn’t a perfect square root.

Question 6

WATCH VIDEOS ABOUT DIFFERENT KIND OF NUMBERS.

Answer 6

::/

Question 7

What does ∈ in X∈A mean? (in sets)

Answer 7

“belongs to” a set, but people just say “in” a set

Question 8

ex.
A = {1,2,3,4,5}
What does this mean?
1∈A, 2∈A, 3∈A

Answer 8

1 in A, 2 in A, 3 in A
1 is an element of A
2 is an element of A
and so on.

Question 9

ex.
A = {6,7,8,9,10}
What does this mean?
6∉A, 7∉A, 8∉A, 9∉A, 10∉A

Answer 9

6 is not in A, 7 is not in A, 8 is not in A, 9 is not in A, 10 is not in A.

6 is not an element/object of A
7 is not an element/object of A
8 is not an element/object of A
9 is not an element/object of A
10 is not an element/object of A
and so on.