$\frac{9}{10}$ m of ribbon is cut into shorter pieces. Each shorter piece of ribbon measures $\frac{1}{4}$ m except for the last piece.
What is the length of the last piece of ribbon?
Express your answer as a fraction in its simplest form. Answer: ___ m

1. Find the number of full pieces of ribbon that can be cut

Number of full pieces = $\frac{9}{10} \div \frac{1}{4} = \frac{9}{10} \times 4 = \frac{36}{10} = 3 \frac{6}{10} = 3 \frac{3}{5}$
So, there are 3 full pieces.

2. Calculate the total length of the full pieces

Length of 3 full pieces = $3 \times \frac{1}{4} = \frac{3}{4}$ m

3. Find the length of the last piece

Length of the last piece = $\frac{9}{10} - \frac{3}{4} = \frac{18}{20} - \frac{15}{20} = \frac{3}{20}$ m