\( \begin{array}{r} 11 \\ -\$ 2 \\ -\$ 5.40 \\ \$ 6.40 \\ \hline \end{array} \)

Let's break this down step by step! Starting with 11 and subtracting $2, we get $9. Then, subtracting $5.40 brings us down to $3.60. Finally, adding $6.40 means we end up with $10.00! So, if you're keeping track of your personal budget or trying to juggle expenses, always remember to double-check each step to avoid those pesky calculation errors that can sneak in. Keeping your numbers organized can make a world of difference!