Mia bought 10 1/9 lb of flour. she used 2 3/4 lb of flour to bake a banana cake and some to bake a chocolate cake. after baking two cakes, she had 3 5/6 lb of flour left. how much flour did she use to bake the chocolate cake?

We know that she started with 10 1/9 pounds and after the two cakes she was left with 3 5/6. So if we subtract what she started with minus what she is left with we will get what she used.

This is easiest done by converting the mixed numbers into improper fractions, finding a common denominator and subtracting (subtract the numerators and keep the denominator) as follows:



That's how much flour she spent on both cakes. If we subtract from this what she spent on the banana cake 2 3/4 we will be left with what she used for the chocolate cake.

This is found as follows:

She used pounds of flour on the chocolate cake.