-
Question 1: Represent $\sqrt{9.3}$ on the number line.
Solution:
1. Draw a line segment AB = 9.3 units.
2. Extend AB to C such that BC = 1 unit.
3. Find the midpoint O of AC.
4. Draw a semicircle with center O and radius OA.
5. Draw a perpendicular at B intersecting the semicircle at D.
6. BD = $\sqrt{9.3}$. With B as center and radius BD, draw an arc to cut the number line at E. Point E represents $\sqrt{9.3}$. -
Question 2: Simplify: $(256)^{-(4^{-3/2})}$
Solution:
First solve the exponent: $4^{-3/2} = \frac{1}{4^{3/2}} = \frac{1}{(2^2)^{3/2}} = \frac{1}{2^3} = \frac{1}{8}$.
Now, expression becomes $(256)^{-1/8}$.
$256 = 2^8$, so $(2^8)^{-1/8} = 2^{8 \times (-1/8)} = 2^{-1} = \frac{1}{2}$. -
Question 3: If $x = 3 + 2\sqrt{2}$, find the value of $x + \frac{1}{x}$.
Solution:
$\frac{1}{x} = \frac{1}{3+2\sqrt{2}} \times \frac{3-2\sqrt{2}}{3-2\sqrt{2}} = \frac{3-2\sqrt{2}}{9-8} = 3-2\sqrt{2}$.
$x + \frac{1}{x} = (3+2\sqrt{2}) + (3-2\sqrt{2}) = 6$. -
Question 4: Express $0.00\overline{32}$ in the form $p/q$.
Solution:
Let $x = 0.003232\dots$
$100x = 0.3232\dots$ (i)
$10000x = 32.3232\dots$ (ii)
Subtract (i) from (ii): $9900x = 32 \Rightarrow x = \frac{32}{9900} = \frac{8}{2475}$. -
Question 5: Visualize $4.\overline{26}$ on the number line up to 4 decimal places ($4.2626$).
Solution:
Use the process of successive magnification:
1. Locate between 4 and 5.
2. Magnify 4.2 to 4.3.
3. Magnify 4.26 to 4.27.
4. Magnify 4.262 to 4.263.
5. Mark 4.2626. -
Question 6: Express $0.6 + 0.\overline{7} + 0.4\overline{7}$ in the form $p/q$.
Solution:
$0.6 = \frac{6}{10}$.
$0.\overline{7} = \frac{7}{9}$.
$0.4\overline{7} = \frac{47-4}{90} = \frac{43}{90}$.
Sum $= \frac{6}{10} + \frac{7}{9} + \frac{43}{90} = \frac{54 + 70 + 43}{90} = \frac{167}{90}$. -
Question 7: Simplify: $4\sqrt{81} - 8(216)^{1/3} + 15(32)^{1/5} + \sqrt{225}$.
Solution:
$= 4(9) - 8(6^3)^{1/3} + 15(2^5)^{1/5} + 15$
$= 36 - 8(6) + 15(2) + 15$
$= 36 - 48 + 30 + 15 = 33$. -
Question 8: If $a = 2 + \sqrt{3}$, find the value of $a - \frac{1}{a}$.
Solution:
$\frac{1}{a} = \frac{1}{2+\sqrt{3}} \times \frac{2-\sqrt{3}}{2-\sqrt{3}} = 2-\sqrt{3}$.
$a - \frac{1}{a} = (2+\sqrt{3}) - (2-\sqrt{3}) = 2 + \sqrt{3} - 2 + \sqrt{3} = 2\sqrt{3}$. -
Question 9: Represent $\sqrt{5}$ on the number line.
Solution:
Construct a right-angled triangle with base 2 units and height 1 unit.
Hypotenuse $= \sqrt{2^2 + 1^2} = \sqrt{5}$.
Using a compass, transfer this length to the number line starting from 0. -
Question 10: Find two irrational numbers between $0.1$ and $0.12$.
Solution:
Irrational numbers are non-terminating and non-repeating.
Example 1: $0.1010010001\dots$
Example 2: $0.110110011000\dots$