Example: 30 and 42 Factor them. 2 x 3 x 5 = 30 2 x 3 x 7 = 42 Select the common factors. 2 x 3 = 6, the GCF Example: 1/30 and 1/42 Factor them. 2 x 3 x 5 = 30 2 x 3 x 7 = 42 Combine the factors, eliminating duplicates. 2 x 3 x 5 x 7 = 210, the LCD
Example: 1/30 and 1/42Factor the denominators.2 x 3 x 5 = 302 x 3 x 7 = 42Combine the factors, eliminating duplicates.2 x 3 x 5 x 7 = 210, the LCDConvert each fraction by multiplying by what's missing.30 x 7 = 21042 x 5 = 2101/30 x 7/7 = 7/2101/42 x 5/5 = 5/210
Example: 1/30 and 1/42Their LCD is 210.Multiply each one by whatever it takes to make 210 in the denominator.30 x 7 = 21042 x 5 = 2101/30 x 7/7 = 7/2101/42 x 5/5 = 5/210
You need at least two fractions to find something in common.
Find the LCM of the denominators. Convert the fractions to equivalent fractions with a common denominator. Example: 1/30 and 1/42 Factor them. 2 x 3 x 5 = 30 2 x 3 x 7 = 42 Select the highest amount of each factor. 2 x 3 x 5 x 7 = 210, the LCD 1/30 = 7/210 1/42 = 5/210
The LCD is 30.
30 over 42 can be reduced to 5/7
30
30
30
The lowest common denominator of 5/42 and 7/30 is 210.
42/30 = 7/5
30/42 = 15/21 = 5/7
Example: 1/30 and 1/42 Factor them. 2 x 3 x 5 = 30 2 x 3 x 7 = 42 Combine the factors, eliminating duplicates. 2 x 3 x 5 x 7 = 210, the LCD 1/30 = 7/210 1/42 = 5/210
30/42 = 15/21 = 5/7
The least common denominator of 5/6 and 4/7 is 42. To set them equal, the fractions would be converted to 35/42 and 24/42.
30/42 = 5/7 = 10/14