That way might eventually get you the answer, and it shows creativity on your part in trying the use of a decimal 1.5 to get the 30 denominator to become 45. However, you should avoid decimals when possible. The LCD of 30 and 45 is 90. so multiply top and bottom of the first fraction by 2 and multiply top and bottom of the second fraction by 3, to get both denominators to become 90. Edwin