Help me with these 3 Math problems please ;[ ?

Question

In simplest form and try to explain it out to me cause i dont get it:

12 3/4
-
8 2/5
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Pronounced as: 12 and 3 forths minis




10 9/10
-
5 1/5
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Pronounced as:10 and 9 tenths minus 5 and 1 fifths





Last one:


4 1/4
-
2 7/8
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Pronounced as: 4 and 1 forth minus 2 and 7 eigths

Answer 1

Ok, first thing you need to know is that whenever you are adding or subrtacting fractions they MUST have the same denominator(base number). So, for the first question:
12 3/4 - 8 2/5 = ?
Alright you don't want both whole numbers and fractions so make them all fractions. If you have 12 3/4 it means that you have 12 full quarters and three extra right? I.e. you can simplify that to be 51/4. (I got fifty one because if you multiply 12 by 4 you get 48 then add the extra 3)
51/4 - 8 2/5 = ?
Next you have to simplify 8 2/5. Once again it means you have eight full fifths so you can change that to 42/5 (again multiply 8 by 5 [40] and add the extra 2)
51/4 - 42/5 = ?
Alright, now you have to find the lowest common denominator for 4 and 5. easiest way to do this is multiply them together then simplify your answer later. So if we multiply 4 by 5 we get 20. So to get 4 to equal 20 you have to multiply it by 5 right? So take the equation 51/4 and multiply it by 5
(51 x 5) / (4 x 5)
= 255 / 20
So 255/20 - 42/5
Next you change the 42/5 to the LCD(lowest common denominator) so to get 20 from 5 you multiply by 4.So multiply 42/5 by 4
(42 x 4) / (5 x 4)
= 168 / 20
So now you have both fractions with the same denominator,
255/20 - 168 / 20
So now that the bottoms are the same you can subtract the tops.
255-168 (still all over 20 remember)
= 87 / 20
Now ask yourself is this in it;s lowest possible terms (meaning can either number be eually divided by the same number?) The answer is no so now you just have to simplify. So if you have 87 twentiths, working backwards from what we did up top, we know that we can see how many times 20 will go into 87.
87/20
= 4 with a remainder of 7
(if you multiply 4 by 20 you get 80 and since we know that this means you have 4 whole twentiths you can simplify the fraction to a mixed number)
So you can write the finale answer as
4 7/20

I hope you understood all that and that it at least clears it up a little. As for the other two questions hopefully you can do them on your own now. Just remeber adding or subtracting must have the same denominator at all times.

Good Luck, Music

Answer 2

So what you want to do is start by making the two numbers into one fraction so (12*4)+3=51 so 12 and 3/4 is equal to 51/4. Do the same with 8 2/5 and you get 42/5. Now in order to subtract these you need common denominators so 51/4 needs a 5 in the denomanator and 42/5 needs a 4. So you can multiply 51/4 by 5/5 to get 255/20 and 168/20 from 42/5. Now all you need to do is subtract 168 from 255 to get 87/20. You can check my math but the reason you can multiply by 5/5 and 4/4 is because those two are both equal to 1 and when you multiply by 1 you get the same thing. Also if you didn't get the first part it's basically reversing what you do to simplify a fraction. When simplifying a fraction you divide the numerator by the denomanator and leave the remaining in the fraction so you multiply the two to reverse it. Hope that helps! Try the other two yourself you can get them


To check your answers i got
57/10 and 11/8
check my math someone

Answer 3

pronounced as 12 and 3 fourths minus 8 and 2 fifths
12 3/4=(12x4+3)51/4 = 255/20
8 2/5=(8x5+2) 42/5 = 168/20 (you multiply the denominator by
225-168= 57 the other denominator)
57/20 is your answer
(this is already simplified because 57 and 20 dont share a comon divider, otherwise, you would find a number that could divide both 57 and 20 and once both were divided, you would have a simplified fraction.)

do you get it?
if not, post an update and ill do the rest for you and further explain it

Answer 4

ok follo my step to step instructions i make math fun..........
41/4
-
27/8
find a common denominator (the bottom numbers hav to be the same)
so say you want to take 2 7/8 and 4 1/4 take the higher number because 8 is dividable by 4 goes into 8 2 times so wat you do to the denominator you do to the numerator.multiply 4 *2 to make 8 and 1 also by 2 to make 2 now you hav4 2/8 .....if 8/8 = 1 (and it does) then take the two from 2 7/8 and put it in to 8/8 form so after you transfer both you hav
34/8
-
23/8
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drop the 8s and bring them down
34
-
23
----------
/8
then do the subtraction problem
34
-
23
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11 /8= 1 3/8 because you put the 11 into 8 as many times as it will make 1 and then the remander (ex.3 ) is put over 8. hope this helped if not email me but plz giv me the 10 points for trying hard lol [e-mail] thx

Answer 5

Convert to mixed numbers
51/4 - 42/5

Find common denominator
255/20 - 168/20

Subtract
87/20
=4 and 7/20

Next
109/10-26/5
109/10-52/10
57/10
5 and 7/10

Next
17/4-23/8
34/8-23/8
11/8
1 and 3/8