PIENSA Y RESUELVE \( 1 / 2 \) de mis bolitas son rojas y \( 5 / 8 \) do las mismas son azules. El resto son blancas. Si tengo 32 bo- litas, ¿cuantas son blancas?

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

2. \( 235-89= \)

Evaluate \(\sqrt ( \frac { 0.0961} { 4.0836- 3.7112} ) \) , correct to four decimal places, hence write the answer in the right form. 

(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)

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