Without seeing the actual wording of the assignment, I would assume this simply means "floating point notation". E.g.,
123.456 can be written 1.23456 x 10^2 or 1.23456e2
.0123456 can be written 1.23456 x 10^-2 or 1.23456e-2
You can use lowercase e or uppercase E for the exponent. What is the actual wording of the assignment?