Expert: Josh - 1/28/2009

Question
How do I solve this problem  2 1/2 x 1 5/9 x 1 2/7this is very confusing for me

Answer
Crissy,

One way to multiply mixed fractions (i.e., numbers with an integer part and fraction part) is to first convert each term into an improper fraction. An improper fraction is an equivalent expression for a mixed fraction, where the numerator exceeds the denominator.

For example, 2 1/2 actually represents 2+(1/2). We can write this as (2*2+1)/2 = 5/2. Likewise, 1 5/9 represents 1+(5/9), we can write this as (1*9+5)/9=14/9. I'll leave you to figure out the equivalent expression for 1 2/7.

Then, you just multiply all the terms directly in the numerator; and all the terms directly in the denominator to obtain the final answer.

e.g., 2 1/2 x 1 5/9 = 5/2 x 14/9 = 70/18 ....which we can simplify as 35/9.

Suppose that 1 2/7 is equivalent to A/B for some number A and B which you calculated a moment ago. The answer to 2 1/2 x 1 5/9 x 1 2/7 is just (5 x 14 x A)/(2 x 9 x B). Further simplification may be necessary if you can find any common factors between the numerator and denominator.