ConTeXt  ver: 2012.07.17 16:42 MKIV  fmt: 2012.7.17  int: english/english

(...)

! Missing $ inserted.

system          > tex > error on line 3 in file test.tex: Missing $ inserted ...

1     \starttext

2     \startformula \startalign

3 >>  v &= u + at \\

4     h &= ut + \frac12 gt^2 \\

5     \stopalign \stopformula

6     \stoptext