Now that you’re majoring in one of the technical disciplines
(engineering, science, or math), you’re going to be spending a
significant amount of time communicating in writing with others. You may find
that previously unimportant details, such as crossing your z’s,
now become essential — not only so that others can understand you, but
also so that you can avoid mistaking your own 2^z for
z² and so on. This is especially important if your
handwriting (like mine!) is less than perfect.

Before I continue, take a fresh look at our Roman alphabet, the digits, and
the Greek alphabet:

Notice that these mechanically typeset symbols are all clear and distinct
(except that lowercase omicron and most of the uppercase Greek letters look
like Roman letters — we don’t use these “duplicates”).

When we write by hand, though, symbols can become ambiguous —
we’re not machines, and things get a little loopy when we hurry. In
prose, surrounding letters can disambiguate a questionable letter — e.g.
you can guess that the fourth letter of hou*e has to be an s.
But in mathematical expressions we mix symbols from different alphabets, in
different orders, so context can’t assist us — and when we guess,
we often guess wrong. So it now becomes very important that each letter be
clearly recognizable on its own merits.

Here are samples, followed by the points I consider most important.

Lowercase Roman letters:

• Always make the lowercase l cursive —
  otherwise it looks like a 1.
  Make sure it’s taller than an e:
  ,
  ,
  .
  The lowercase l isn’t a good variable name to use (since it can
  look like a 1), but lots of people use it and so yo