1 1/4-3 3/5- 2 1/2

To solve this expression, we need to subtract the given fractions and mixed numbers.

First, let's convert the mixed numbers to improper fractions:

1 1/4 = (4*1 + 1)/4 = 5/4
3 3/5 = (5*3 + 3)/5 = 18/5
2 1/2 = (2*2 + 1)/2 = 5/2

Now, the expression becomes:

5/4 - 18/5 - 5/2

To subtract fractions, we need a common denominator. The least common denominator (LCD) for 4, 5, and 2 is 20.

Multiplying the first fraction by 5/5, the second by 4/4, and the third by 10/10, we get:

(5/4)*(5/5) - (18/5)*(4/4) - (5/2)*(10/10)
= 25/20 - 72/20 - 50/20

Now, we can subtract the fractions:
25/20 - 72/20 - 50/20 = (25 - 72 - 50)/20 = -97/20

Therefore, 1 1/4 - 3 3/5 - 2 1/2 = -97/20.