Solve the following integer and common fraction problems showing all steps: -23 - (-18), 2(8-3+4), 33 + 42 - 52, sqrt(9) + 16 + 7, (-6+3(-4)-3(4))/((2+3)(-3)), and 10 divided by 5/8.

$$= -5$$

The result is $\boxed{\mathbf{-5}}$.

$$2(8-3+4) = 2(5+4)$$ $$= 2(9)$$

$$= 18$$

The result is $\boxed{\mathbf{18}}$.

$$3^3 = 27$$ $$4^2 = 16$$ $$5^2 = 25$$

$$43 - 25 = 18$$

The result is $\boxed{\mathbf{18}}$.

$$3 + 16 + 7 = 19 + 7$$ $$= 26$$

The result is $\boxed{\mathbf{26}}$.

$$-6 + 3(-4) - 3(4) = -6 - 12 - 12$$ $$= -30$$

$$(2+3)(-3) = (5)(-3)$$ $$= -15$$

$$\frac{-30}{-15} = 2$$

The result is $\boxed{\mathbf{2}}$.

4. COMMON FRACTIONS

$$= \frac{10 \times 8}{5}$$ $$= \frac{80}{5}$$

$$= 16$$

The result is $\boxed{\mathbf{16}}$.

$$= \frac{5}{7}$$

The simplified expression is $\boxed{\mathbf{\frac{5}{7}}}$.

Find a common denominator, which is 12.

$$\frac{2}{3} + \frac{1}{4} = \frac{2 \times 4}{3 \times 4} + \frac{1 \times 3}{4 \times 3}$$ $$= \frac{8}{12} + \frac{3}{12}$$ $$= \frac{8+3}{12}$$ $$= \frac{11}{12}$$

The simplified expression is $\boxed{\mathbf{\frac{11}{12}}}$.

$$\text{Decrease} = \text{Original Price} - \text{New Price}$$ $$\text{Decrease} = \text{R}10 - \text{R}7 = \text{R}3$$

$\frac{\text{Decrease}}{\text{Original Price}} \times 100\%$.

$$\text{Percentage Decrease} = \frac{\text{R}3}{\text{R}10} \times 100\%$$ $$= 0.3 \times 100\%$$ $$= 30\%$$

The percentage decrease is $\boxed{\mathbf{30\%}}$.