Finding Common Denominators What is a denominator? –The bottom part of a fraction that represents the total parts of the whole 6/6 What is a common denominator? – The possible ways that fractions can be used to add or subtract unlike numbers. They can ONLY be solved by finding a common denominator. Multiples- the product of a whole number multiplied times any other whole number. Ex: Some multiples of 6: 6, 12, 18, 24, 30, 36, 42 Common Multiple- a number that is a multiple of two or more numbers Ex: Some multiples of 3 & 6: 6, 12, 18, 24, 30, 36, 42 Least Common Multiple- the smallest common multiple of a set of two or more numbers. Lowest multiple that two numbers have in common. EX: 5= 5, 10, 15, 20 25, 30 6= 6, 12, 18, 24, 30, 36 TO ADD AND SUBTRACT FRACTIONS WITH UNLIKE DENOMINATORS… STEP 1: Find the multiples of each denominator STEP 2: Compare the lists of multiples. Circle the common multiples between the two lists. SHORTCUT for L.C.D. Check to see if the smaller denominator divides evenly into the larger denominator. If it does, use the larger denominator for Your LCDn .