although it's not possible to be sure what is really meant, without a compilable example, this sounds like the
equation environments are set without any text between, like this:
this isn't recommended. instead, it's possible to nest an
align group within
[6pt] is optional; it assumes that some additional space is wanted between the aligned material and the non-aligned equations. (this optional directive can be used at any line break to increase or decrease the space between lines.)
all lines will be numbered, unless
\notag is used on individual lines, or
aligned is used to omit the number from that entire group.