We are presented with some coercion functions and asked

### Ex 4.1: Why is `inchToPixel x` not defined as `100 * round`

x ?

x

It is instead defined as `round(100 * x)`. This is because if

rounding was done on the input parameter, then whether it was, say, 1.01

or 1.99, the answer would be the same: 100*(round 1.01) = 100*1 = 100.

### Ex 4.2 Why is `pixelToInch n` not defined as `intToFloat`

(n/100)

(n/100)

Similarly, this is to do with fixity/order of application of

expressions: The version above would first try to evaluate

`n/100`, which will fail, as `n` is an Integer, and

â€œ`/`â€œ isn't defined for Ints.

That's it for the exercises. I played along with the examples, which

basically amounts to copying out of the book – actually I think that's

more instructive than just reading or getting the source code off the

internet, because it helps develop finger-memory.

Well, he does leave a â€œyou may wish to define these functions on your

own as an exerciseâ€, but right now, I'm going to bed instead.