Subtrating and estimationg fracions Fractions?

Question

I will try to attempt to answer these question if I miss a step could someone please correct me and let me know what step I am missing....
1/3+5/12+4/5= 10/12

13/15-11/20= 2/5

1 1/15+ 3 3/10- 2 4/5= 2 1/5

estimating

17 11/12 divided by 6 1/10 =3 1/2

Answer 1

1/3 + 5/12 + 4/5
Find the common denominator, which is 60.
Change each fraction to have a denominator of 60.
20/60 + 25/60 + 48/60
Now add the numerators to make 93/60
Simplify the fraction 31/20.
Convert to a proper fraction if you need to 1 & 11/20

Next Problem
13/15 - 11/20
Find common denominator which is 60
Change each fraction to have a denominator of 60.
52/60 - 33/60
Now add the numerators to make 85/60
Simplify the fraction 17/12.
Convert to a proper fraction if you need to 1 & 5/12

Next problem.
1 1/15 + 3 3/10 - 2 4/5
Convert to improper fractions.
16/15 + 33/10 - 14/5
Find common denominator, which is 30.
Change each fraction to have a denominator of 30.
32/30 + 99/30 - 84/30
Now add (or subtract) the numerators to make 47/30
Convert to a proper fraction if you need to 1 & 17/30

Next Problem.
It's fairly close to 18 divided by 6 which is 3.
Or if you want the precise answer.
17 11/12 divided by 6 1/10
Convert to improper fractions.
215/12 divided by 61/10
Change equation into multiplication by reciprocating the right side.
215/12 multiplied by 10/61
Multiple the numerators and denominators strait across.
2150/732
Simplify
1075 / 366
Convert to proper fraction if needed 2 & 343/366

Answer 2

in order to add and subtract fractions, you have to find the least common denominator first. you have to find a number that will make each fraction have the same number in the denominator.

In the first one, the LCD is: 60 because 3 * 20 = 60, 12 * 5 = 60, and 5 * 12=60.

(1/3)(20/20) = 20/60 = 1/3
(5/12)(5/5) = 25/60 = 5/12
(4/5)(12/12) = 48/60 = 4/5

93/60 = (31 * 3) / (20 * 3) = 31/20

Once you do that, you add the numerator normally, while keeping the denominator the same.

In the second one the LCD is 60 also because 15 * 4 = 60 and 20 * 3 = 60. With 13/15, you multiply by 4/4 (which is one and doesnt change the value) to give you: 52/60.
for the second one you multiply 11/20 by 3/3 which is: 33/60.

now you do the subtraction: 52/60 - 33/60 = 19/60.

for the third one, you'd have to convert the mixed numbers into improper fractions and then do the LCD method. in order to do that, you multiply the whole number by the denominator and add the result to the numerator.
for example:

1 1/15 = 16/15. (1*15 + 1) = 16
3 3/10 = 33/10. (3 * 10 + 3) = 33
2 4/5 = 14/5. (2 * 5 + 4) = 14

the LCD for this one is 30. 15 * 2 = 30, 10 * 3 = 30, and 5 * 6 = 30.

16/15 * 2/2 = 32/30
33/10 * 3/3 = 99/30
14/5 * 6/6 = 84/30

32/30 + 99/30 - 84/30 = 47/30.

with the last one, 17 11/12 is almost 18 and 6 1/10 is almost 6.
18/6 = 3. so about 3.

Answer 3

I'm not sure what you're trying to do here - and I'm a former math teacher. Is each of the first three lines a separate problem, and you're supposed to add up the numbers to the left of the equal sign, and the number after the equal sign is your answer? If so, you need to redo them. To add and subtract fractions, you need to first find the least common denominator. That's the smallest number that each of the denominators (bottom numbers) of all the fractions you're trying to add goes into evenly. For the first line, since the denominators are 3,12 and 5, the smallest number they all go into is 60. So you'd have to convert each fraction into something over 60, then add them up, then simplify if possible, which means that if there's some number that goes evenly into both the top and bottom of your resulting fraction, you divide both by that number.

For the last line, if they're just asking you to estimate the answer rather than find an exact answer: 17 11/12 is almost 18. 6 1/10 is just a little over 6. So the answer if you calculate it exactly should be something close to 18/6, which is 3.

Answer 4

When adding or subtracting fractions, the KEY is find a common denominator and then add or subtract.

Now I tell my students that it's best to convert any mixed fractions into improper ones (number on top and a number on the bottom) because it makes it easier to handle.

To convert mixed to improper, you multiply the whole number by the denominator, and then add the numerator to it.

Look at the denominators you have and find a number they all have in common. That would be your "new denominator." For example, if I need to add 1/4 and 1/3, they both have 12 in common, so 12 would be my new denominator.

Then convert each fraction into this new denominator, and add the numerators together and stick it over the new denominator. If you need to reduce, do it. And if you need your answer as a mixed fraction, simply divide numerator by denominator and put any "leftover" / remainder over the denominator.
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When it comes to dividing fractions, the KEY is that you flip-flop the fraction you're dividing by, and then multiply. Again, it's best to convert mixed into improper first.

To multiply fractions, you simply multiply the numberators together to get your new numerator, then multiply your denominators together to get your new denominator.

Example, 2 / 3 x 1 / 2 = ( 2 x 1 ) / ( 3 x 2 ) = 2 / 6, which could be ultimately be reduced down to 1 / 3.

Answer 5

When you add fractions you need to have the same common denominator (so pick a number that all three bottom numbers go into evenly, its called an equivalent fraction) so for your first answer all three denominators go into 60. so you have to now convert all the denominators and numerators.

1/3= 20/60, 5/12=25/60, 4/5=48 (so you just multiply the top number by the same numer as you did the denominator)

then you add them up... 20/60+25/60+48/60=93/60

Do the same when you are subtracting...

To divide y ou have to multiply the numerators together and then the denomenators