Convert the following. Show working to gain full marks2 marks each Convert 5.6 km to metres Convert 2500 mL to Liters Convert 3.5 hours to seconds Convert 7 800m to kilometres Convert 2.4 kg to grams Convert 25 days to seconds

$$
1 \text{ km} = 1000 \text{ m}
$$

$$
5.6 \text{ km} \times 1000 \frac{\text{m}}{\text{km}} = 5600 \text{ m}
$$
The converted value is $\boxed{\textbf{5600 m}}$.

$$
1 \text{ L} = 1000 \text{ mL}
$$

$$
2500 \text{ mL} \div 1000 \frac{\text{mL}}{\text{L}} = 2.5 \text{ L}
$$
The converted value is $\boxed{\textbf{2.5 L}}$.

$$
1 \text{ hour} = 60 \text{ minutes}
$$
$$
1 \text{ minute} = 60 \text{ seconds}
$$

$$
3.5 \text{ hours} \times 60 \frac{\text{minutes}}{\text{hour}} \times 60 \frac{\text{seconds}}{\text{minute}} = 12600 \text{ seconds}
$$
The converted value is $\boxed{\textbf{12600 seconds}}$.

$$
1 \text{ km} = 1000 \text{ m}
$$

$$
7800 \text{ m} \div 1000 \frac{\text{m}}{\text{km}} = 7.8 \text{ km}
$$
The converted value is $\boxed{\textbf{7.8 km}}$.

$$
1 \text{ kg} = 1000 \text{ g}
$$

$$
2.4 \text{ kg} \times 1000 \frac{\text{g}}{\text{kg}} = 2400 \text{ g}
$$
The converted value is $\boxed{\textbf{2400 g}}$.

$$
1 \text{ day} = 24 \text{ hours}
$$
$$
1 \text{ hour} = 60 \text{ minutes}
$$
$$
1 \text{ minute} = 60 \text{ seconds}
$$

$$
25 \text{ days} \times 24 \frac{\text{hours}}{\text{day}} \times 60 \frac{\text{minutes}}{\text{hour}} \times 60 \frac{\text{seconds}}{\text{minute}} = 2160000 \text{ seconds}
$$
The converted value is $\boxed{\textbf{2160000 seconds}}$.

$$
1 \text{ m} = 100 \text{ cm}
$$
$$
\text{Length} = 8 \text{ m} \times 100 \frac{\text{cm}}{\text{m}} = 800 \text{ cm}
$$
$$
\text{Width} = 5 \text{ m} \times 100 \frac{\text{cm}}{\text{m}} = 500 \text{ cm}
$$

$$
\text{Area} = \text{Length} \times \text{Width}
$$
$$
\text{Area} = 800 \text{ cm} \times 500 \text{ cm} = 400000 \text{ cm}^2
$$
The area of the classroom is $\boxed{\textbf{400000 cm}^2}$.

$$
1 \text{ m}^3 = 1000 \text{ L}
$$

$$
0.75 \text{ m}^3 \times 1000 \frac{\text{L}}{\text{m}^3} = 750 \text{ L}
$$
The volume in Liters is $\boxed{\textbf{750 L}}$.