# SICP - Solution: Exercise 2.8

##### January 10, 2019

## 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))))
```