For the sake of example, let's multiply the two numbers

and

together. Altogether, we have:

Rearranging the expression, we can group the exponents and coefficients together:

Multiplying each out, we notice that since

and

have the same base (10), multiplying them has the effect of adding their exponents, which leaves us with:

The takeaway here is that multiplying two numbers in scientific notation together has the effect of multiplying its coefficients and
adding its exponents.