Number systems and sets of numbersIB MYP Maths Extended: Mind map

Exam questions on Number systems and sets of numbers

1. Consider the numbers in the set $S=\{-3,\ 0,\ \frac{2}{5},\ \sqrt{16},\ \sqrt{7},\ 0.\dot{3},\ \pi\}$.
   Write down the elements of $S$ that are rational but not integers.2 marks
2. Let $A=\{x\in\mathbb{Z}:-2\le x<3\}$ and $B=\{0,\ 2,\ 4,\ 6\}$.
   Write down $A\cup B$ and state the value of $n(A\cup B)$.2 marks
3. Consider the numbers $\sqrt{49}$, $\sqrt{48}$, $-\frac{9}{4}$, $0.45$, $\frac{\pi}{2}$ and $-\sqrt{25}$.
   For each of $\sqrt{49}$, $-\sqrt{25}$ and $\frac{\pi}{2}$, state the smallest of the sets $\mathbb{N}$, $\mathbb{Z}$ and $\mathbb{Q}$ that contains it, or state that it is irrational.3 marks