For numbers 14a-14d , tell which expressions require you to rename mixed numbers before you can subtract. Find each difference. write each expression and the difference in the correct box.
14a 5 2/5 - 2 1/4
14b 5-2 7/8
14c 7 2/3 - 6 1/8
14d 9 1/6 - 5 2/3

Respuesta :

OK, so turn 5 and  2/5ths into a fraction greater than one which would be 27/5ths. Then take the 27/5ths and find the least common denominator, which should be 20. Multiply 27/5ths by 4 and you should have 108/20 and turn the 2 and 1/4 into a 20, so then turn that into a number greater than one which you should get 9/4ths, do the same thing as you did before only this time multiple by 5. You should now get, 45/20ths, now subtract 108/20ths  and 45/20ths. Now, after that, you should have your answer which is 63/20 or 3 and 3/20ths.

Answer:

14b and 14d require renaming mixed numbers; 14a) 3 3/20; 14b) 2 1/8; 14c) 1 13/24; 14d) 3 3/6 = 3 1/2

Step-by-step explanation:

14a) First we find the least common denominator (LCD).  The first thing that both 5 and 4 will divide into is 20; this is our LCD.

It takes 4 5's to make 20; multiplying the numerator by 4, we have 5 8/20.  It takes 5 4's to make 20; multiplying the numerator by 5, we have 2 5/20.  Subtracting these,

5 8/20 - 2 5/20 = 3 3/20

14b) We must write the whole number 5 as a mixed number with a denominator of 8; 5 = 4 8/8.  This gives us

4 8/8 - 2 7/8 = 2 1/8

14c) The LCD of 3 and 8 is 24.  It takes 8 3's to make 24; multiplying the numerator by 8, we have 7 16/24.  It takes 3 8's to make 24; multiplying the numerator by 3, we have 6 3/24.  Subtracting we have

7 16/24 - 6 3/24 = 1 13/24.

14d) The LCD of 6 and 3 is 6.  Since the first mixed number has a denominator of 6, we leave it:  9 1/6.  It takes 2 3's to make 6; multiplying the numerator by 2, we have 5 4/6.  Subtracting we would have

9 1/6 - 5 4/6

We are subtracting a larger fraction from a smaller one.  This means we borrow a whole from the whole number, making it 8; this makes the fraction (6+1)/6 = 7/6.  This gives us

8 7/6 - 5 4/6 = 3 3/6 = 3 1/2

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