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fractions calculations add and subtract 2

fraction problem 2:


Determine the lowest common denominator and calculate the value, reduce the solution and write as a mixed fractions if possible! 
 
3/5 – 1 1/4 + 3 3/10 =
 

answer:


the lowest common denominator:

5 = 1  * 5 

4 = 2 * 2      

10 = 2 * 5 

2 * 2 * 5 = 20

 

calculate the value:

to make the bottom numbers the same you have to multiply the top and the bottom of 

the first fraction with 4    (because  5 * 4 = 20) 

the second fraction with 5  (because  4 * 5 = 20) 

the third fraction with 2   (because 10 * 2 = 20) 

 
13/5 – 5/4 + 33/10 =  
 
 13*4/5*4 – 5*5/4*5 + 33*2/10*2 =  
 
 52/20 – 25/20 + 66/20 =  
 
118/20  25/2  93/20 
 
write as a mixed fraction:
 
93/20 = 4 13/20        (93 : 20 =  4 and 13/20)