Pre-Alegebra fraction problem...?

Question

I can't figure out how the answer to the following problem is 13/18. Help please!

1/2 + (2/3 + 3/4) - (4/5 x 5/6)

Answer 1

The answer is:

1/2+(2/3+3/4=8/12+9/12)=(17/12)

1/2+(17/12)-(4/5 x 5/6= 20/30)

1/2+(17/12)- (20/30)

30/60 + 85/60 - 40/60= 115/60-40/60= 75/60= 15/12

Answer 2

= 1/2 + (8/12 + 9/12) - (4/6)

= 1/2 + 17/12 - 8/12

= 6/12 + 17/12 - 8/12

= 15/12

= 5/4

If they want a mixed fraction, 1 1/4

If they want a decimal, 1.25

Hope that helps.

Answer 3

it equals 1 1/4 hon

Answer 4

1/2 + (2/3 + 3/4) - (4/5 x 5/6)

=1/2 + (8/12 + 9/12) - (2/3)

=1/2 + 17/12 - 2/3

=23/12 - 2/3

= 23/12 - 8/12

= 15/12

= 5/4 or 1 and 1/4

I dont know how it equals 13/18 either...they might've made a miscalculation though

Answer 5

1/2 + (2/3 + 3/4) - (4/5 x 5/6) =

   You always start with the parentheses and work your way from the inside out. When adding or subtracting fractions you must have a common denominator, when multiplying or dividing fractions you don't. Once you've multiplied the fractions in the last set of parentheses you can determine a common denominator and begin adding.

   When you multiply (4/5 x 5/6), the 5 in the denominator of 4/5 cancels out with the 5 in the numerator of 5/6 leaving 4/6 as the answer.4/6 can be reduced to 2/3.

   Now you need a common denominator. Your fractions are 1/2, 2/3, 3/4 and another 2/3 from your previous multiplication. Looking at 2,3, and 4 your lowest common denominator is 12 ... 1/2 = 6/12, (1/2 x 6/6 = 6/12), 2/3 = 8/12 (2/3 x 4/4 = 8/12), 3/4 = 9/12 (3/4 x 3/3 = 9/12).

   Replace the original fractions with the equivalent fractions that are now in 12's.

1/2 + (2/3 + 3/4) - (2/3) =

6/12 + (8/12 + 9/12) - 8/12 =

Work the parentheses first (8/12 + 9/12 = 17/12)

And then finish by working left to right

6/12 + (17/12) - 8/12 =

23/12 - 8/12 = 15/12    (which reduces to 5/4 or 1 1/4)

Sorry, but 13/18 is wrong ...  go through this slowly and it should make sense.

Check out this site for more help: www.purplemath.com/modules/index.htm

Good luck!

Answer 6

Try to find a common denominator to your fractions and/or set the problem equal to zero and see if that helps.  

Answer 7

yes its...

http://www.intmath.com/Numbers/exp.gif

Answer 8

multiply the denominaters and the numerators that should give you 20/30, find the least common denominator of 3 and 4, 12, multiply 4 and 2, and then 3 and 3, to get 9/12 and 8/12, add, 1 and 5/12 should be your answer find least common denominator of 12 and 30, should get 60 multiply 5 and 12 by 5, multiply 20 and 30 by 2. 25/60, and 40/60 are what you should get subtract 40 from 60, got 60 from the 1 in front of 5/12, should get 20, add 20 to 25. should get 45/60, add 30, half of 60, to 45, should get 75, answer is 1 and 15/60, reduce. should get1/4.

Answer 9

when you add or subtract fractions you have to give them a common denominator. when you multiply just multiply the numerators and the denominators. the least common denominator for 2/3 and 3/4 is 12.

so 2/3 = 8/12 and 3/4 = 9/12

now back to the equation:

1/2 + (2/3 + 3/4) - (4/5 x 5/6)

1/2 + (8/12 + 9/12) - (20/30)

1/2 + 17/12 - 2/3  <--- i simplified 20/30 to 2/3

the least common denominator here is also 12:

1/2 = 6/12  and -2/3 = -8/12

so...

1/2 + 17/12 - 2/3 is now...

6/12 + 17/12 - 8/12

23/12 - 8/12

15/12

5/4

are you sure you typed in the problem correctly? either that or the book is wrong which happens every now and then.

Answer 10

I get 15/12 with the rest of them... if that is the answer in the book, there is often errors in the answer section, so I wouldn't trust it too much.