To convert a mixed number to its lowest form, one needs to change the mixed number into an improper fraction and then reduce this improper fraction to the lowest possible fraction. To do these conversions, one needs to perform a few calculations. One also has to understand the definitions of "mixed number," "improper fraction" and "proper fraction."
A proper fraction is a fraction that has a lower number in the numerator and a higher number in denominator, such as the fraction three-fourths. An improper fraction is the inverse of this, which entails the higher number in numerator and lower number in the denominator, like 5/3. A mixed number is a whole number with a fraction, such as 1 3/4.
To convert the mixed number 1 3/4, one has to multiply the denominator 4 by the whole number 1 that gives 4, add this 4 to the 3 in the numerator to get 7 and place 7 over the denominator to find the improper fraction 7/4. In this case, this is the lowest form for this mixed number. However, if the mixed number is 6 4/6, then this converts to the improper fraction 40/6. One can divide the numerator and denominator of 40/6 by 2 to find that 20/3 is the lowest form for the mixed number 6 4/6.