01. Types of numbers

Question 1

LEVEL 4

Select the rational number from the list below:

A: \sqrt{81}

B: \sqrt{90}

C:  \sqrt{20}

D:  \sqrt{42}

CORRECT ANSWER: A: \sqrt{81}

WORKED SOLUTION:

\sqrt{81} = 9

9 is an integer so rational.

Question 2

LEVEL 4

Select the irrational number from the list below:

A: \sqrt{16}

B: \sqrt{49}

C: \sqrt{2}

D: \sqrt{121}

CORRECT ANSWER: C: \sqrt{2}

WORKED SOLUTION:

\sqrt{2} can not be made by dividing two integers so is irrational.

Question 3

LEVEL 3

Select the integer number from the list below:

A: \dfrac{35}{10}

B: \dfrac{10}{3}

C: \dfrac{20}{10}

D: \dfrac{40}{6}

CORRECT ANSWER:   C: \dfrac{20}{10}

WORKED SOLUTION:

\dfrac{20}{10}=2

2 is an integer.

Question 4

LEVEL 4

Select the rational number from the list below:

A: \dfrac{\pi}{2}

B: \dfrac{1}{\sqrt{2}}

C: \dfrac{\sqrt3}{3}

D: \dfrac{3}{8}

CORRECT ANSWER:  D: \dfrac{3}{8}

WORKED SOLUTION:

\dfrac{3}{8} is a fraction of two integers so is rational.

Question 5

LEVEL 4

Select the irrational number from the list below:

A: \dfrac{-1}{2}

B: 0.4

C: \dfrac{1}{3}

D: \pi

CORRECT ANSWER: D: \pi

WORKED SOLUTION:

\pi is an irrational number.