Hope this helped you!
/21 and /84
/28 and /42
/28 and /84
/42 and /84
/84 and /84
Answer:
Any with denominators of which their lowest common multiple is 84; for pairs of fractions these are:
whole numbers and /84
/2 and /84
/3 and /28
/3 and /42
/3 and /84
/4 and /21
/4 and /42
/4 and /84
/6 and /28
/6 and /84
/7 and /12
/7 and /84
/12 and /14
/12 and /21
/12 and /28
/12 and /42
/12 and /84
/14 and /84
/21 and /28
There are further possible fractions when there are three at a time, and so on upwards. With 12 fractions at a time they can all have different denominators, namely:
whole numbers, /2, /3, /4, /6, /7, /12, /14, /21, /28, /42 and /84
Though there are other possibilities with one or more repeated denominators.
With 13 or more fractions, some of them of necessity will have the same denominator since there are only 12 factors of 84, namely: 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42 & 84.