10. En un dia, una persona entrega una copia de una oración al Espiritu Santo a 3 de sus amigos. Al día siguiente de recibir la oración, cada uno de los receptores debe entregar copia de ella a cada uno de 3 amigos distintos del que se la envió. ¿Al final del quinto día, cuántas copias de la oración se estarán repartiendo?

2. \( 235-89= \)

18. \( 10^{2}+3^{3}-2 \times 3= \) 19. \( 4^{2}+(7+2) \div 3= \) 20. \( 7 \times 4-9 \div 3= \)

Simplify these fractions. \( \begin{array}{ll}\text { (15) } \frac{16}{20}= & \text { (18) } \frac{9}{81}= \\ \text { (16) } \frac{4}{128}= & \text { (19) } \frac{16}{20}= \\ \text { (17) } \frac{10}{15}= & \text { (20) } \frac{30}{445}=\end{array} \)

11. \( \frac{-3(9-7)}{7+9-2^{3}}= \) 12. \( \frac{4-(2+7)}{13+(6-9)}= \) 13. \( \frac{5(3-8)-2^{2}}{7-3(6+1)}= \)

(a) What was the TOTAL cost of the stamps? (b) She had to post a parcel and the total cost of postage was \( \$ 25.70 \). What stamps can she select from the collection, to make up this amount if she must use (i) as many \( \$ 4.00 \) stamps as possible? (ii) all her \( \$ 1.00 \) stamps? 3 marks) (c) 2 marks) (i) What is the LARGEST number of stamps that she can use from the collection (ii) List the selection of stamps she can use. 3 marks)