Video instructions and help with filling out and completing When Form 8815 Subtract

Instructions and Help about When Form 8815 Subtract

So welcome to my video on subtracting mixed numbers here we have 3 and 3/4 being subtracted by 1 and 7/8 and the first thing I like to do and I wrote this for you and green is I like to convert the mixed numbers to improper fractions and then subtract and I do realize that there are quicker ways to subtract mixed numbers however this method which I'm teaching is guaranteed to work the same way for every single problem whereas the other methods that might be a little quicker are not guaranteed to work the same way for every single problem so let's just get started right away let's convert our mixed numbers into improper fractions we'll start first to a 3 and 3/4 since this mixed number has a 4 in the denominator our improper fraction is also going to have a 4 in the denominator and then in the numerator we have to multiply the denominator 4 with the whole number of 3 so 4 times 3 is equal to 12 and then we have to add that with our numerator of 3 and this is all being subtracted with 1 and 7/8 so let's do the same thing with this mixed number let's change it into an improper fraction since it has a denominator of 8 the improper fraction is also going to have a denominator of 8 and in the numerator we multiply the 8 by the whole number of 1 8 times 1 is 8 and then we add all that to the numerator of 7 so let's simplify these two fractions in the first fraction we have 12 plus 3 in the numerator 12 plus 3 is equal to 15 and our denominator stays the same and this is all being subtracted by our second fraction which has a numerator of 8 plus 7 which is just 15 as well and our denominator of 8 stays the same so now when you subtract or add two fractions you have have common denominators that means that both denominators have to be the same so since we have one denominator which is a 4 and another denominator which is an 8 we have to make them both the same so I'm going to multiply the 4 times a 2 which gives us 2 times 4 which is 8 and then both denominators will be the same and you have to remember whatever you do to the bottom of a fraction you have to do to the top of a fraction so since we multiply the bottom by 2 we have to multiply the top by 2 as well so now let's simplify the first fraction in the numerator we have 2 times 15 2 times 15 is 30 and in the denominator we have 2 times 4 which is 8 and our second fraction stays the same and now since we have common denominators of 8 we can subtract these fractions really easily whenever you're subtracting fractions the denominator stays the same since we have a denominator of 8 our answer is also going to have a denominator of 8 and in the numerator we're just going to subtract the two numerators so we have 30 minus 15 so now we can simplify this even further in our numerator we have 30 minus 15 which is just 15 and our denominator of 8 stays the same so now we have an improper fraction of 15 over 8 as our answer however since we're subtracting mixed numbers our final answer should also be a mixed number so I'm going to change 15 over 8 into a mixed number and this can be done using long division I'm going to divide 15 by 8 8 goes in to 15 one time 1 times 8 is 8 and if you subtract 15 minus 8 we have a 2 remainder of 7 since it goes into 15:1 whole time our mixed number is also going to have a whole number of one and since we have seven left over and our remainder our numerator is also going to have a seven in our mixed number and since we have an eight and a denominator of the fraction we're also going to have an eight in the denominator of the mixed number so 15 over 8 is exactly the same as one in seven eighths and this is our final answer so here are some more videos with some more example problems related to the video you just watched I really hope you're finding my tutorials helpful so until my next video I will see you later