Video instructions and help with filling out and completing When Form 2220 Subtracting

Instructions and Help about When Form 2220 Subtracting

In this video we're going to focus on add and subtract and multiplying and dividing mixed numbers or mixed fractions so let's start with our first example 3 + 1 4 5 + 2 + 3 fifth how can we add these two fractions there's two ways in which you can do it 3 and 1/4 is basically 3 plus 1/4 - and 3/5 is 2 plus 3 over 5 so we can add 3 + 2 and that's going to turn into 5 and then separately we can add 1/4 + 3/5 but we need to get common denominators but for now let's rewriting so 1/4 or 3/5 our own proper fractions one way in which you can add to improper fractions is you can multiply 1 + 5 + 4 + 3 which is 12 and then you can multiply the two denominators 4 times 5 is 25 + 12 that's 17 so it's 17 over 20 so 1/4 + 3 fifths is 17 over 20 + 5 + 17 over 20 is 5 17 over 20 so that's how you can add two mixed numbers now keep in mind another way in which you can add 1/4 + 3 fifths if you do not like that first technique you can do it this way you can get common denominators so we can multiply the first fraction by 5 and the second fraction top and bottom by 4 so 1 times 5 is 5 5 times 4 is 20 and 3 times 4 is 12 5 + 12 is 17 so we're going to get the same fraction 17 but our final answer is still gonna be the same so you can use either of those two techniques to add to improper fractions now let's try another example 5 and 2/3 + 4 + 1 / 7 go ahead and try this example pause the video work out the problem and see what answer you get and then unpause the video to see the solution the best way to learn is by trying these problems yourself is by doing the work so this is 5 + 4 + 2 / 3 + 1 / 7 5 + 4 adds up to 9 and to add 2 / 3 and 1 / 7 we need to get common denominators so I'm going to multiply this by 3 over 3 and the other fraction by 7 over 7 2 times 7 is 14 7 times 3 is 21 3 times 1 is 3 so now we can add the numerators now that we have like denominators 14 plus 3 is 17 + 9 + 17 over 21 well that's 9 + 17 over 21 so this is the final answer as a mixed fraction let's try another example 7 and 3/4 + 6 + 2 fifths let's add these two so we can add 7 + 6 that's going to be 13 and now we need to add 3/4 + 2 / 5 so let's use the first technique that we started with in the beginning 3 times 5 is 15 and 4 times 2 is 8 and 4 times 5 is 20 now let's add 15 plus 8 15 + 8 is 23 so therefore the answer is 1323 over 20 but notice that 23 over 20 is greater than 1 so we can reduce it let's break down 23 over 20 into 20 over 20 plus 3 over 20 we can do that because 23 is 20 plus 3 now 20 over 20 that's 1 so we can rewrite this as 14 + 3 over 20 13 + 1 is 14 and so this is the final answer as it fraction in its simplest form so now let's add a whole number to a mixed number so what's the answer to this problem the answer is simply 5 plus 6 which is 11 so it's 11 and 3/4 keep in mind 6 and 3/4 is 6 plus 3/4 so you can add 5 & 6 directly to get 1111 plus 3/4 is 11 and 3/4 so if you wish to add 7 plus 9 and 2/3 it's simply 16 and 2/3 so that's all you need to do if you wish to add a whole number to a mixed number so now let's move on into subtraction what is 7 and 2/3 minus 5 and 1/4 there's two things that we can do we can convert each mixed number into an improper fraction and then subtract or we could separate the mixed numbers into whole numbers and improper fractions and then subtract let's convert it into an improper fraction first to convert 7 and 2/3 into an improper fraction the denominator is going to stay the same on top it's going to be 7 times 3 plus 2 for the other one the 4 is going to remain on the bottom on top it's going to be 5 times 4 plus 1 so seven times string is 2121 plus two is 23 five times four is 20 plus one that's 21 so we have 23 over three minus 21 over 4 so now let's get common denominators let's multiply this side by three and the other side by four so what is 4 times 23 4 times 20 is 80 4 times 3 is 12 80 plus 12 is 92 and 4 times 3 is 12 which we said that already so that's going to be the bottom for both fractions 21 times 3 20 times 3 is 60 1 times 3 is 3 60 Plus 3 is 63 so now what is 92 minus 63 2 minus 3 is a negative number so let's borrow a 1 if we borrow a 1 from 9 it turns into 8 but the 2 turns into 12 so 12 minus 3 is 9 8 minus 6 is 2 so 92 minus 63 is 29 so our answer is 29