25/63
It is: 1/7 of 63 = 9
It is: 3/7 of 63 = 27
It has to be 7x9 or 63 or less. There is no number less than 63 which is divisible by both 7 and 9 therefore 63 is the LCD.
3/7 of 63 is 27.
36
27
63
28/63 + 36/63 = 64/63 = 1 and 1/63
5/7 * 63 315/7 = 45 ----------
28/63
4 sevenths just over half