Question

So here's the question

Answer 1

Yes, is subtraction, to get their "difference".

first off, let's convert the mixed fractions, to "improper", and then subtract.

$\bf \stackrel{red~yarn}{9\frac{1}{5}}-\stackrel{blue~yarn}{3\frac{11}{25}}$

$\bf -------------------------------\\\\ \stackrel{mixed}{9\frac{1}{5}}\implies \cfrac{9\cdot 5+1}{5}\implies \stackrel{improper}{\cfrac{46}{5}} \\\\\\ \stackrel{mixed}{3\frac{11}{25}}\implies \cfrac{3\cdot 25+11}{25}\implies \stackrel{improper}{\cfrac{86}{25}}\\\\ -------------------------------\\\\ \cfrac{46}{5}-\cfrac{86}{25}\impliedby \textit{our LCD is 25}\implies \cfrac{(5\cdot 46)~~-~~(1\cdot 86)}{25} \\\\\\ \cfrac{230~-~86}{25}\implies \cfrac{144}{25}\implies 5\frac{19}{25}$