@kent f OBE wrote:
does anyone remember how to find the common denominator? coz I’ll be damned if I can :roll:
In mathematics, the lowest common denominator or least common denominator (abbreviated LCD) is the least common multiple of the denominators of a set of vulgar fractions. It is the smallest positive integer that is a multiple of the denominators. For instance, the LCD of
is 36 because the least common multiple of 12 and 18 is 36. Likewise the LCD of
is 12. Using the LCD (or any multiple of it, such as the product of the denominators) as a denominator enables addition, subtraction or comparison of fractions:
The lowest common denominator of two vulgar fractions can be found by calculating the least common multiple of their denominators.
Some K-12 ballons standards such as the latest revision of the NCTM math standards and reform mathematics textbooks created since the 1990s de-emphasize or omit coverage of the LCD entirely in favor of finding any common, but not necessarily the lowest common denominator, or by using less powerful methods such as fraction strips or “benchmark” fractions. The “cross-multiply” method of comparing fractions effectively creates a common denominator by multiplying both denominators together.
does that help :?