Convert the following measurements into the indicated units: a) 6 m to mm, b) 22000 mm to m, c) 9 km to m. Also, convert the following to kilometers: a) 4200 m, b) 800,000 cm, c) 645,000 m.

Step 1: Answer question 1.
The relationships between units of length measurement are:

• $1 \text{ kilometer (km)} = 1000 \text{ meters (m)}$
• $1 \text{ meter (m)} = 100 \text{ centimeters (cm)}$
• $1 \text{ centimeter (cm)} = 10 \text{ millimeters (mm)}$

Step 2: Convert the given values to kilometers for question 2.

a) Convert $4200 \text{ m}$ to $\text{km}$:

$$4200 \text{ m} \times \frac{1 \text{ km}}{1000 \text{ m}} = 4.2 \text{ km}$$

b) Convert $800,000 \text{ cm}$ to $\text{km}$:

$$800,000 \text{ cm} \times \frac{1 \text{ m}}{100 \text{ cm}} \times \frac{1 \text{ km}}{1000 \text{ m}} = 8 \text{ km}$$

c) Convert $645,000 \text{ m}$ to $\text{km}$:

$$645,000 \text{ m} \times \frac{1 \text{ km}}{1000 \text{ m}} = 645 \text{ km}$$

The answers are: a) $\boxed{4.2 \text{ km}}$, b) $\boxed{8 \text{ km}}$, c) $\boxed{645 \text{ km}}$.

Step 3: Convert the given values to the required units for question 3.

a) Convert $6 \text{ m}$ to $\text{mm}$:

$$6 \text{ m} \times \frac{100 \text{ cm}}{1 \text{ m}} \times \frac{10 \text{ mm}}{1 \text{ cm}} = 6000 \text{ mm}$$

b) Convert $22000 \text{ mm}$ to $\text{m}$:

$$22000 \text{ mm} \times \frac{1 \text{ cm}}{10 \text{ mm}} \times \frac{1 \text{ m}}{100 \text{ cm}} = 22 \text{ m}$$

c) Convert $9 \text{ km}$ to $\text{m}$:

$$9 \text{ km} \times \frac{1000 \text{ m}}{1 \text{ km}} = 9000 \text{ m}$$

The answers are: a) $\boxed{6000 \text{ mm}}$, b) $\boxed{22 \text{ m}}$, c) $\boxed{9000 \text{ m}}$.

Step 4: Answer questions 4 and 5. 4. Examples of small units of measurement are: millimeter (mm), centimeter (cm). 5. Examples of large units of measurement are: kilometer (km), meter (m).

Step 5: Convert mass units for questions 6, 7, 8, 9, 10, 11, 14, 15, 16, 20.
Assume $1 \text{ ton (t)} = 1000 \text{ kg}$ and $1 \text{ Ku (quintal)} = 100 \text{ kg}$. 6. Convert $30 \text{ kg}$ to $\text{g}$: $30 \text{ kg} \times \frac{1000 \text{ g}}{1 \text{ kg}} = 30,000 \text{ g}$ The answer is $\boxed{30,000 \text{ g}}$. 7. Convert $0.02 \text{ t}$ to $\text{g}$: $0.02 \text{ t} \times \frac{1000 \text{ kg}}{1 \text{ t}} \times \frac{1000 \text{ g}}{1 \text{ kg}} = 20,000 \text{ g}$ The answer is $\boxed{20,000 \text{ g}}$. 8. Convert $9 \text{ Ku}$ to $\text{g}$: $9 \text{ Ku} \times \frac{100 \text{ kg}}{1 \text{ Ku}} \times \frac{1000 \text{ g}}{1 \text{ kg}} = 900,000 \text{ g}$ The answer is $\boxed{900,000 \text{ g}}$. 9. Convert $800 \text{ Ku}$ to $\text{g}$: $800 \text{ Ku} \times \frac{100 \text{ kg}}{1 \text{ Ku}} \times \frac{1000 \text{ g}}{1 \text{ kg}} = 80,000,000 \text{ g}$ The answer is $\boxed{80,000,000 \text{ g}}$. 10. Convert $7500 \text{ kg}$ to $\text{Ku}$: $7500 \text{ kg} \times \frac{1 \text{ Ku}}{100 \text{ kg}} = 75 \text{ Ku}$ The answer is $\boxed{75 \text{ Ku}}$. 11. Calculate $20 \text{ t} + 9 \text{ Ku}$ in $\text{kg}$: $20 \text{ t} = 20 \times 1000 \text{ kg} = 20,000 \text{ kg}$ $9 \text{ Ku} = 9 \times 100 \text{ kg} = 900 \text{ kg}$ $20,000 \text{ kg} + 900 \text{ kg} = 20,900 \text{ kg}$ The answer is $\boxed{20,900 \text{ kg}}$. 14. Calculate $10 \text{ kg} + 1000 \text{ g}$ in $\text{Ku}$: $1000 \text{ g} = 1000 \text{ g} \times \frac{1 \text{ kg}}{1000 \text{ g}} = 1 \text{ kg}$ $10 \text{ kg} + 1 \text{ kg} = 11 \text{ kg}$ $$11 kg \times \frac{1 Ku}{100 kg} = 0.11 \text