5. \( \frac{11}{5}+\frac{4}{21} \) of \( 42-\frac{18}{5} \div \frac{27}{45} \)

3.1. Simplify each of the following ratios: 3.1.1. \( 4: 28: 16 \) 3.1.2. \( 6: 1.25: 2.5 \) 3.1.3. \( 3.6: 27: 13.5 \) 3.2. Distribute \( R 24000.00 \) in the ratio 2:1:5.

Aşağıdaki sayıların 9 ile bölünebilmesi için gelebilecek rakamların tamamını yazınız. 7. \( 10 \square 27 \rightarrow \) 8. \( 657 \square \rightarrow \) 9. \( 555555 \square \rightarrow \ldots \)

Ex. 3 Simplify \( \left(9.6 \times 3.6 \div 7.2+10.8\right. \) of \( \left.\frac{1}{18}-\frac{1}{10}\right) \)

11. If the average (arithmetic mean) of five numbers is 4 and if four of the numbers are \( 1,3,5 \), and 7 , what is the fifth number? \( \begin{array}{llll}\text { (A) }-1 & \text { (B) } 0 & \text { (C) } & \text { (D) } 6\end{array} \) (E) 9 \( \$ \begin{array}{l}\text { (D) }\end{array} \)

(ii) \( \begin{array}{r}5.129 \times(-0.15) \\ .23 \\ 5.129 \times 6\end{array} \)