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What is negative 5 4ths minus positive 2 3rds??

im doing homework and im super confused?!

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Donald M. | Award Winning EducatorAward Winning Educator
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Any time you are ading or subtracting fractions you want to find like denominators. So first list the multiples of each denominator until you find the smallest number they have in common.

At my school the younger children call it skip counting. 4,8,12

Do the same with the 3=3,6,9,12. So 3and 4 have least common denominator or 12. then you take each fraction and multiply both numbers that gave you the least common denominator.

-5/4 x 3/3= -15/12 do thesame with the second fraction 2/3 x4/4 = 8/12

now you have -15/12 - 8/12 this is the same as -15/12 + -8/12 = -23/12 or -1 and11/12 as a mixed number.

 

Jaison N. | A PhD to Teach You Math and PhysicsA PhD to Teach You Math and Physics
4.9 4.9 (150 lesson ratings) (150)
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Let's first rewrite this problem in terms of somthing less confusing.

-5/4 - 2/3 each has a -1 in front of it.

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

Now, each term has a -1 in front, which means you can factor it out

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

Look what I have done here. I've done a reverse distribution to turn the problem into one of addition.

Now, find the least common denominator which is 12.

(-1)( 15/12 + 8/12 ) = (-1)(23/12) = -23/12

Jennifer K. | Math, Reading, Writing, and Computer TutorMath, Reading, Writing, and Computer Tut...
5.0 5.0 (1 lesson ratings) (1)
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You need to remember that a negative minus a positive is the same as saying

-5/4  +   -2/3 

 

find the common demoniatior of 4 and 3 ..... 12

-5/4 then becomes -15/12

-2/3 becomes        -8/12

Add the -15/12 + -8/12 = -23/12

If you need to simplify:  Divide -23 by 12  = -1  and 11/12 or