find lowest common denominator with the given denominators, 13/15 - 11/20

Would the LCD be 60?

60/15= 4
60/20 = 3

To find the lowest common denominator (LCD) for the fractions 13/15 and 11/20, we need to find the least common multiple (LCM) of the denominators 15 and 20.

First, let's find the prime factorizations of 15 and 20:

15 = 3 × 5
20 = 2^2 × 5

Next, we identify the highest power of each prime factor. In this case, we have:

Highest power of 2: 2^2
Highest power of 3: 3
Highest power of 5: 5

Now, we multiplicatively combine the highest powers of each prime factor:

2^2 × 3 × 5 = 60

Therefore, the LCD for the fractions 13/15 and 11/20 is 60.

To find the lowest common denominator (LCD) between 15 and 20, we need to find the least common multiple (LCM) of these two numbers.

To find the LCM, we can use the prime factorization method:

Step 1: Prime factorize each number.

15 = 3 x 5
20 = 2^2 x 5

Step 2: Write down the prime factors of both numbers, including the repeated factors.
The prime factors of 15 are 3 and 5.
The prime factors of 20 are 2, 2 and 5.

Step 3: Multiply all the prime factors together, including the repeated factors.
2 x 2 x 3 x 5 = 60

Therefore, the least common multiple (LCM) of 15 and 20 is 60.

Now, let's convert the given fractions to have a common denominator of 60:

13/15 = (13/15) x (4/4) = 52/60

11/20 = (11/20) x (3/3) = 33/60

Now that both fractions have the same denominator of 60, we can subtract them:

52/60 - 33/60 = (52 - 33)/60 = 19/60

Therefore, the result of the subtraction 13/15 - 11/20 is 19/60.