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(4/6) + (3/8) +  7  =

2/3 + 3/8 +  7 =  [ common denominator is 24 ]

16/24 + 9/24 + 7 =

25/24 + 7 =

1 + 1/24 + 7 =

8 + 1/24

3/4 - 5/6 - 2/3 =   [common denominator  is 12]

9/12 - 10/12 - 8/12  =

-1/12 - 8/12 =

-9/12 =

-3/4

5 (6/7)^2  =

5 (6/7)(6/7)  =

5 (36/49) =

180 / 49

(4/5   /   1/3 ) * (5/8)   invert the second fraction and multiply

(4/5 * 3/1 ) * (5/8)  =

(12/5) * (5/8) =     swap denominators

(12/8 * 5/5) =

(12/8 * 1)  =

12/8  =

3/2

(3/7 - 2/3) + (4/5) (2/3) =    common denominator between the first two fractions is 21

(9/21 - 14/21) + (8/15)  =

(-5/21) + (8/15)   commond denominator  = 7 * 3 * 5  = 105

(-25/105) + (56/105)  =

31/105

4/6 + 3/8 + 7 = 193/24 or 8 & 1/24

3/4 - 5/6 - 2/3 = -3/4

5(6/7)² = 180/49

5/8([4/5]/[1/3]) = 3/2

(3/7 - 2/3) + (4/5) (2/3) = 31/105