1. Work out $2 \frac{2}{3} \times \frac{1}{6} + 1 \frac{3}{8}$. - Convert mixed numbers to improper fractions: $2 \frac{2}{3} = \frac{8}{3}$ and $1 \frac{3}{8} = \frac{11}{8}$. - Multiply $\frac{8}{3} \times \frac{1}{6} = \frac{8}{18} = \frac{4}{9}$. - Add $\frac{4}{9} + \frac{11}{8}$. - Find common denominator: $72$. - Convert fractions: $\frac{4}{9} = \frac{32}{72}$, $\frac{11}{8} = \frac{99}{72}$. - Add: $\frac{32}{72} + \frac{99}{72} = \frac{131}{72} = 1 \frac{59}{72}$. 2. Calculate $\frac{1}{3}$ of 15 minus $3 \times \frac{1}{4} \div 3$. - $\frac{1}{3} \times 15 = 5$. - $3 \times \frac{1}{4} = \frac{3}{4}$. - Divide $\frac{3}{4} \div 3 = \frac{3}{4} \times \frac{1}{3} = \frac{1}{4}$. - Subtract: $5 - \frac{1}{4} = \frac{20}{4} - \frac{1}{4} = \frac{19}{4} = 4 \frac{3}{4}$. 3. Find the place value of digit 6 in 3689417132. - The digit 6 is in the hundred millions place. - Place value = $600000000$. 4. Express 72 as a product of its prime factors. - $72 = 2 \times 36 = 2 \times 2 \times 18 = 2^3 \times 3^2$. 5. List prime numbers between 90 and 100. - Prime numbers are 97. 6. Share 445801 among 89 workers. - Divide: $445801 \div 89 = 5009$. 7. Reciprocal of $\frac{7}{6}$. - Reciprocal is $\frac{6}{7}$. 8. Water tank problem: capacity 7500 litres, daily use 356 litres for 18 days. - Total used: $356 \times 18 = 6408$ litres. - Remaining: $7500 - 6408 = 1092$ litres. 9. Number of males if total adults 719944 and females 285204. - Males = $719944 - 285204 = 434740$. 10. Distance 3.65 km in metres. - $3.65 \text{ km} = 3.65 \times 1000 = 3650$ metres.