What is the least common denominator when adding the fractions a / 2, b / 3, c / 9, and d / 15?
A. 45
B. 90
C. 135
D. 270
E. 810
Will it be 90?
Because 2 x 9 x 15 = 90
Oh. I apologize.
2 x 9 x 5 = 90. I realized my mistake.
Yes. 90 is correct.
No.
I'm sorry. I don't know what I'm doing.
Study this site carefully.
http://www.mathsisfun.com/least-common-denominator.html
2: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20
3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30
9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90
15: 15, 30, 45, 60, 75, 90, 105, 120, 135, 150
so the LCD is 90
Only three of those are divisible by 2.
Which one is also divisible by 3, 9, and 15?