First, find their LCD
Like 3/4 + 2/3 + 1/5 = n
Their LCD is 60. Then find its numerator by dividing the LCD to the denominator and multiplying it do the numerator.
(60 ÷ 4)3 = 45
(60 ÷ 3)2 = 40
(60 ÷ 5)1 = 12
Now, we have 45/60, 40/60, and 12/60.
Add their numerators and reduce it to lowest term. That's simple ☺
45 + 40 + 12 = 97
97/60 to mixed number is 1 17/60
That's it.
