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

10 answers

Only three of those are divisible by 2.

Which one is also divisible by 3, 9, and 15?
Will it be 90?
Yes. 90 is correct.
Because 2 x 9 x 15 = 90
No.
Oh. I apologize.
2 x 9 x 5 = 90. I realized my mistake.
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