Whats the lcd of 1/7,14/17,12/13,5/6

LCD (1/7, 14/7, 12/13, 5/6)

LCM = (7, 7, 13, 6)

=  2 * 3 * 7 * 13

=  546

1/7  = 78/546

14/7  = 1092/546

12/13  = 504/546

5/6  = 455/546

Calculation:

1/7 + 14/7 

= 1 + 14/7

=  15/7

The common denominator you can calculate as the least common multiple of the both denominators:   LCM (7, 7) = 7

Add:

15/7 + 12/13 

= 15 . 13/7. 13  + 12 . 7/13 . 7

= 195/91 + 84/91

=  195 + 84/91 

=  279/91

The common denominator you can calculate as the least common multiple of the both denominators:  LCM (7, 13) = 91

Add:

279/91 + 5/6

= 279 . 6/91 . 6 + 5 . 91/6. 91

= 1674/546 + 455/546

= 1674 + 455/546 

= 2129/546

The common denominator you can calculate as the least common multiple of the both denominators:  LCM (91, 6) = 546

Hence, 546 is the LCM/LCD of (1/7, 14/17, 13/13, 5/6).

Hope that helps