# SICP - Solution: Exercise 2.8

## Jan 10, 2019 07:09 · 40 words · 1 minute read

**Exercise 2.8:** Using reasoning analogous to Alyssa’s, describe how the difference of two intervals may be computed. Define a corresponding subtraction procedure, called `sub-interval`

.

**Solution**

```
(define (sub-interval x y)
(make-interval (- (lower-bound x)
(upper-bound y))
(- (upper-bound x)
(lower-bound y))))
```