Dividing Decimals - Decimal Divisors | 5th Grade Math

welcome to fifth grade math with mr. J so in this video we are going to be getting into dividing decimals with decimal divisors now if you watched my last video it was dividing decimals with whole number divisors and much like that video or process of dividing decimals by whole number divisors it's the same long division process as any division problem okay this one just takes a little extra step whenever you have a decimal divisor or decimal outside number it just takes a little extra step but as long as you know the division process you will be good to go if you want to go check out whole number divisors first dividing decimals by whole number of divisors if you miss that video I drop the link to my instructional video down in the description and then you can come back to decimal divisors I would have something to write without and write these out with me I think that will be beneficial so here we go with number one we have seventy one and two tenths divided by two tenths now if you remember from my whole number divisor videos I said you should ask yourself a question before you start any division problem and that question is is my divisor whole and remember if your divisors whole you bring that decimal straight up well in number one here our divisor is not whole so we do not bring our decimal straight up what we do is we have to make our we have to make our divisor whole we have to make it whole and we move the decimal to do this okay which is the same as multiplying by a power of 10 moving the decimal once is like multiplying by 10 moving it twice by a hundred three times thousand four times 10,000 and so on so for number one here we have had we would have to move the decimal once which is like multiplying by 10 now whatever you do to the outside to the divisor you have to do to the inside or the dividend so I move my decimal once here so I literally draw those arrows out to show my movements and then I rewrite my problem my divisor is two and now I have 712 as my dividend doing this moving that decimal will put the decimal in the correct place for my quotient so now I just go through my long division process 7/2 well three whole groups of two out of seven three times two is six subtract I get one bring down my one 11 divided by 2 is 5 5 times 2 is 10 subtract I get 1 bring down this 2 and now 12 divided by 2 which is 6 6 times 2 is 12 I get a clean cut 0 and a whole number answer here so 356 would be my quotient ok so to recap always check if your divisors whole if not you need to make it whole do the same thing to the inside and outside and then go through your long division process so let's go to number 2 here we have 49 and 6 tenths divided by 4 hundredths is my divisor whole know so I need to make it whole and in this one I need to move the decimal twice which is the same as multiplying by 100 whatever I do to the outside I need to do the inside 1/2 there's my decimal fill with a 0 here so rewrite my problem 4 is my divisor and 4960 is my dividend and now I just go through my long division process 4 divided by 4 is 1 1 times 4 is 4 subtract I get 0 bring down that 9 9 divided by 4 is 2 2 times 4 is 8 subtract I get one bring down that six 16 divided by 4 is 4 4 times 4 is 16 subtract I get 0 and bring down the 0 and here is one of the most common mistakes when it comes to division because we have a zero down here we think we're done but in reality we are not done we need to go all the way over to our lowest place value here which is the ones place we need to fill that spot with something so you still have to think you have to do 0 divided by 4 how many groups of 4 are and 0 well that can't happen right 0 divided by 4 is 0 so 0 times 4 is 0 subtract now we are done we went all the way over so our quotient would be 1240 number 3 we have a 1 in 5 tenths as our divisor and 3 and 15 hundredths as our dividend so is our divisor whole no it's in between 1 & 2 it has a whole number right has the 1 but it's not an exact whole number it's in between 1 & 2 so we need to multiply it by a power of 10 and in this one we just need to move the decimal once which is like multiplying by 10 do the same thing to the inside so now my decimal is in between the 1 and the 5 and I have a 15 as my divisor so everything is set up for me now is my divisor now all yes I have the 15 so I can bring that decimal straight up 31 divided by 15 is 2 2 times 15 is 30 subtract I get 1 bring down that 5 now I have 15 divided by 15 which is 1 1 times 15 is 15 subtract I get 0 2 and 1/10 and then finally number four here we have five tenths and 125 as our dividend divisor is not whole so I need to make it whole move the decimal once that means on the inside I need to move my decimal once remember decimals are at the end of whole number so it goes to the end I move it once fill with the 0 so I have 5 as my divisor and 1250 as my dividend now I'm ready to go through my process 12 divided by 5 is 2 2 times 5 is 10 subtract I get to bring down that 5 25 divided by 5 is 5 5 times 5 is 25 subtract I get 0 bring down that zero remember I need to go all the way over I'm not done my answer is not 25 so I need to do 0 divided by 5 which is 0 0 times 5 is 0 subtract I get a 0 now I'm done I went all the way over to my lowest place value my quotient or answer is 250 so that's those are the basics to dividing decimals by decimal divisors so now it's your turn to try some on your own so head over to my mastery check I dropped a link down in the description where you can try 4 on your own to see if you have it down thanks for watching [Music]