help on fractions please?

Question

well i need help on fractions and how to add divide and subtract them
please help
3 examples:
3 1/7 + 2 2/5
8 1/12 - 4 3/4
2 8/7 divide by 8
please help

the way my teacher showed me was 3 1/7= 22/7 and 2 2/5 = 12/5
and dn i gt 24/35
hw ***?

Answer 1

Don't they all make something simple look complicated!

Its so easy

3 1/7 + 2 2/5

Add your whole numbers together 3+2 = 5

now the fractions

1/7 + 2/5 = 5/35 + 14/35 = 19/35

so your answer is 5 19/35

Answer 2

They way I work with fractions may not be the best, but it works for me. For your first example 3 1/7 + 2 2/5, try this: First take the bottom numbers of both parts of the equation (the denominators) and turn them into the lowest common denominator (the lowest number both numbers can be divided into). In this example the LCD is 35. Now look at the fraction 1/7. Change the denominator to 35, then divided by 7 (to get 5), then multiply 5 times the numerator (top number in the fraction) to get 5. So the fraction is now 5/35 instead of 1/7. Using the same method, the denominator for 2/5 is 14/35. Now you ad 5/35 plus 14/35 to make 19/35. There is not number that can be divided into both 19 and 35, so your fraction remains at 19/35. Now just add your whole numbers (3+2) which makes 5, and you have your final answer of 5 19/35. Use this method for both addition and subtraction problems in fractions.

For the division problem, multiply the first number, 2 8/7 like this:
2x8 - 16, and this leaves the same denominator of 7, so now you have 16/7. Next, place a 1 under the number 8, and you have 8/1. Now flip the number you just came up with and you have 1/8. Now instead of dividing, you multiply 16/7 x 1/8. The answer here is 16/56. You can lower this number because the numberator and denominator are both divisible by 8. So if you divide 16 by 8, you get 2. If you divide 56 by 8, you get 7. The numbers cannot be reduced any further because no other number can be divided into both numbers other than 1. So the final answer is 2/7.

Or you can look at it another way. When you look at both numbers you see something in common, which is the number 8. 2 8/7 = 16/7 and 8 = 8/1. Now just write the problem out as 16/7 divided by 8/1. Remember to flip the number on the right side and multiply. You should now have 16/7 x 1/8. The numerator on the left and the denominator on the right are both divisible by 8. So divide 16 by 8 to come up with 2, and divide 8 by 8 to come up with 1. Now multiply, and you have 2/7 x 1/1. This still gives you the answer of 2/7.

Answer 3

In all cases, you need to convert the fractional part to a common denominator (the part on the bottom).

For instance, 1/7 and 2/5. You need to find the smallest number that both 7 and 5 divide into. In this case, it's 35. 7 times 5 is 35, so 1/7 == 5/35. And 2/5 is 14/35. Then you can add the tops.

3 5/35 + 2 14/35 == 5 + 19/35.

The second one is a little easier. You have 1/12 and 3/4. 4 divides into 12 easily (12 / 4 == 3), so you still have 1/12 and 9/12th.

8 1/12 + 4 9/12 = 12 10/12.

Your teacher would want you then to reduce the 10/12ths into a simpler form. Both numbers are even, so divide top and bottom by 2:

12 10/12 = 12 5/6.

And that's your answer.

For the last one... When you divide a fraction (8/7) by a whole number (8), you just divide the whole number into the top of the fraction. So you could consider 8/7 divded by 8 to be (8 / 8) / 7. Or 1/7.

2/8 is 1/4th of course.

So you're left with 1/4th + 1/7. Doing the least common denominator thing again, you have 7/28 + 4/28 == 11/28ths for your final answer.

Answer 4

1>2 2/5 = (5*2+2)/5 = 12/5
3 1/7 = 22/7
22/7 + 12/5. You can only add fractions if the denominators are same.
The LCM of the denominators is 35.
So if we can convert both the denominators into 35, we can add the fractions.
22/7 = 110/35 (Multiplying both the numerator and denominator by 5)
12/5 = 84/35 (Multiplying both the denominator and numerator by 7)
Now adding,
22/7+12/5=110/35+84/35=194/35
Converting this into mixed fraction we get 5 19/35

Solve the second problem in a similar way.

For the third one,2 8/7 divided by 8 is the same as 2 8/7 multiplied by 1/8.
2 8/7 = 22/7
22/7 * 1/8 = 11/28 < Canceling two and multiplying>

Answer 5

To add and subtract, you must first have the same denominator. You multipy the denominator and numerator by the same number.

first one:
3 5/35 + 2 14/35 = 5 19/35

second one:
8 1/12 - 4 9/12 = 3 4/12 = 3 1/3

third one:
2 8/7 / 8/1 = 22/7 / 8/1 = 22/7 * 1/8 =

22/56 = 11/28

Answer 6

1: make them into common denominators

3 1/7 + 2 2/5 = 3 5/35 + 2 14/35 = 5 19/35

2: make into common denominators again

8 1/12 - 4 3/4 = 8 1/12 - 4 9/12 = 3 2/12

3: divide by 8 means multiply by 1/8

2 8/7 divide by 8 = 22/7 x 1/8 = 22/56 = 11/28

Answer 7

To add or subtract fractions, change them to have the same demoninator.
1 1/7 + 2 2/5 = 8/7 + 12/5

7 and 5 are both factors of 35 so change these to be in terms of xxx/35

8/7 + 12/5 = 8x5/35 + 12x7/5 = 40/35 + 84/35 = 124/35 = 3 19/35

As for dividing, multiply the lower number by the number you are dividing by

2 8/7 = 22/7

22/7 / 8 = 22/7x8 = 22/56 = 11/28

Answer 8

3 1/7 = 22/7
2 2/5 = 12/5 then find common denominator which would be 35
84/35 + 110/35 = 194/35 = 5 19/35

Answer 9

To solve the fractions:
1. convert the mixed fractions to inproper fractions
e.g. 3 1/7 =((7*3)+1)/7 =22/7.
2. Take the L C M of the two denominators.
3. (first fraction)* L C M (second fraction)* L C M)/ L C M.
4. The resulting fraction is the answer.
NOTE : - L C M = least common multiple.

To divide : - Multiply the improper fraction by 1/(number).

Answer 10

Its be to get the fraction the same (devisable by the same number) i.e

1/7 (times the 1 & 7 by 5 to get to 35)+ 2/5 (times the 2 & 5 by 7 to get to 35) = 5/35 + 14/35 = 19/35