Since 21 is divisible by 3, the least common denominator of 3 and 21 is 21.
3/21 is equal to 1/7, so your question does not make sense.
21
LCD(9, 21) = 63
The least common denominator (LCD) is 1.
the LCD of 5 and 7 is explanation: 7: 14, 21, 28, 35, 42, 49, 56, 63, 70 5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 so the LCD is 5 and7 is 35
LCD(49, 21) = 147
If you mean lcm, it is 36 because 9 x 4 equals 36 and 3 x 12 equals 36.
21
21.
It is 42
LCD(8, 21, 7) = 168.
21
It is: 294 which is the same as its LCM
LCD(9, 21) = 63
The least common denominator (LCD) is 1.
LCD(18, 21) = 126
The Least Common Denominator (or LCD) is the Least Common Multiple (LCM) of the denominators of a pair of fractions. I assume the 7 and 21 are the denominators of two fractions you need to add or subtract.LCD(7, 21) = 21.
the LCD of 5 and 7 is explanation: 7: 14, 21, 28, 35, 42, 49, 56, 63, 70 5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 so the LCD is 5 and7 is 35
Put as 6/7 - 4/21, change to LCD: 18/21 - 4/21, which is 14/21, or 2/3