hello my name is Maria from math mammoths calm in this lesson we will be converting between metric and customary measuring units and that's a difficult topic for many so I'll try to take it slow okay first of all I wrote here some conversion factors that we will use now besides these there are many more if you have a mathematical table or so but I just wrote some such as one inch is 2.54 centimeters and thence one foot into meters and one mile into kilometers and then one quote into liters and then one ounce is this many grams then one kilogram 2.2 pounds okay so we're gonna use those and my first problem has four point eight two meters in two feet now let's check first of all our conversion factors do we have one between meters and feet yes we do it's one foot equals so many meters okay if this had been one meter equals so many feet because I have here so many meters then I could have just multiplied but now it turns out I need to divide by the conversion factor okay and I want you to think now in each of these problems we will either multiply or divide by the conversion factor but which how do you know whether to multiply or divide here's one way you can know and that is if you know by heart which ones are longer or bigger units meters or feet I hope you know that feet are shoulder okay there's about three feet into one meter meters are the bigger units so if I have almost five meters here in feet I need a bigger number here because feet are smaller units so whether I multiply I divide I have to get a bigger number here then for point a two and my decimal number here the conversion factor if I multiply by it if I this times this I would get a smaller number as a result okay because this number is less than one so I will divide by it this divided by that okay and I'm gonna round it to one one decimal digit it's about fifteen point eight feet and that makes sense okay this is about five meters and I get about three times that many in feet how about 17 kilometers into miles now what would you do would you multiply by this or divide by that okay now our kilometers or miles bigger units along the unit's kilometers are shorter right and so over here this number here has to be a smaller number than 17 because miles are longer units 10 kilometers so I need to divide by it so I can get a smaller number here 17 divided by one point six oh nine three and I get ten point five six about this one I'm gonna skip for now we'll come back to it in a little bit let's take this one because it's easier we have kilograms and pounds here's a factor one kilogram is 2.2 pounds so you can see over here that one kilogram is the bigger unit right I have this many kilograms in two pounds so in pounds I need a bigger number right just like here the number four pounds is the bigger number so in order to get the bigger number I need to multiply by 2.2 okay 120 point five six six gallons three quarts how many liters our conversion factor is one quad equals so many liters almost one liter and here we have gallons I don't have written any conversion factor for gallons here but what I can do is first change this into so many quarts okay each gallon is four quads right so six gallons 24 quad plus three more so that's 27 quads here and now since I have the one quad equals so many liters 27 course equals 27 times the conversion factor in liters okay or you can think over here the number four quarts is bigger than the number four liters and so I need to get a little bit smaller number here which will work when I multiply by this number because this number is less than one okay twenty five point five four two liters then three pounds 15 ounces into kilograms again we have here two units pounds and ounces so we either need to change this separately into kilograms and this separately into kilograms or change this into so many pounds first or change this into something else first okay so there's lots to think about I have the conversion factor for both ounces and pounds okay so there's many ways to do this now let me try if we will change this into ounces first and then since one arms is this many grams then we can multiply by that three pounds how many ounces is it 1 pound 16 ounces right three pounds is 3 times 16 that's 48 plus 15 so we will get 63 ounces right now one ounce is twenty eight point three five grams so 63 ounces 63 times that much our answer is in grams because this is here grams gonna write it here 1786 grams as kilograms it is 1.78 six kilograms and then lastly this one that I skipped here earlier milliliters and fluid ounces now the difficult here is that I do not have a conversion factor written here for fluid ounces and liters okay but I'm gonna make one let's take this first I'm gonna copy it here one quad equals this is in liters I'm gonna write in milliliters now nine four six milli and one quart is 32 ounces liquid ounces of fluid ounces and now I can get the conversion factor between ounces and milliliters okay either by getting one ounce equals so many milliliters or one milliliter equals so many ounces I can do it either way let's do it for 1 ounce equals this number divided by 32 and we get twenty nine point five six two five milliliters okay now milliliters into fluid ounces do we need to divide or multiply if I multiply I would get many thousands of fluid ounces I hope you can see that won't work fluid ounces are bigger units than this so I need to divide okay this about eleven point nine fluid ounces