The meaning of your question isn't clear but twice one third is two thirds - 2/3, six times one seventeenth is 6/17
Any number can be a common multiple of two or more fractions. The concept of common multiples is useful only in the context of multiples of integers.
When reducing fractions to their lowest terms or finding the LCD of fractions
numerators
Kilograms and multiples (or fractions) of it.
Multiply them by successive counting numbers.
When adding or subtracting fractions with different denominators and when reducing fractions to their lowest terms
Use the LCM when you are adding and subtracting unlike fractions. Use the GCF when you are simplifying fractions.
Nothing. Fractions don't have highest terms. Numbers don't stop, multiples don't stop.
The second, along with its fractions and multiples.
Common factors go into the numbers, the numbers go into common multiples.
When adding or subtracting fractions with different denominators and when reducing fractions to their lowest terms.
an exponent