Explanation: Explanation: The main reason why I told you previously to rely on my conversion method is that once the conversion involves multiple units conversion factors, employing my formula is your best bet. Again, Don’t feel stressed out. First, write 45,000 cm. Then, our goal is to reach the km unit. This is hard to do in one step, so we have to apply several conversion methods. So, it is obvious that we have to convert cm→m→ km. Therefore, we can do 45,000 cm x 1m/100cm x 1km/1000m. The confusion and silly mistakes often stem from the fact that students get confused whether to start with 1m/100 cm or 100 cm/1m. Remember what I said in “easy” type examples that our goal is to eliminate the cm(initial condition), so we have to multiply 45 000 cm x 1m/100 cm to eliminate the cm and have m instead. This is equal to 450 m. Should we stop here? No, the question says the end unit should be km. So, we have to multiply 450 m x 1km/ 1000m to eliminate the m unit and ultimately reach the km unit one. It makes sense that 1km/1000m conversion to be used since it satisfies the requirements: eliminating m(unfavorable end unit) and ensuring that km( favoring unit) is in the nominator.

Explanation: This is becoming harder, but the method still thankfully perfectly works. First, start with 720 inches. Given, that our end unit is meters( based on the question), we have to move from inch--> cm--> m. So, 720 inches x 2.54 cm/ 1 inch will yield 1830 cm. Are we done? No. We have to eventually convert 1830 cm into m: 1830 cm x 1m/100 cm= 18.3 m

Explanation: Explanation: Don't stress out if we change the units. You still have to use the same method. First, start with 21 hours. Then, we have to eliminate the hours to eventually have seconds in the numerator to get your final answer in seconds. So, 21 hours x 60 minutes/ 1hour= 1260 minutes will help us find the answer in minutes. Are we done? Not yet. We have to eventually convert it into seconds: 1260 x 60 seconds/ 1minute= 75,600 seconds. I do recommend you to practice doing them in one long step, especially you might encounter multiple conversions in the future. See the image below for a long, but 1-step calculation.