## Elementary Algebra

In order to write a number in scientific notation, we must use the form $n \times 10^a$, where n is a number between 1 and 10 and a is the number of places the decimal of the original number has to be moved left to get the number n. (If the decimal is moved right, a is negative.) Using this gives: a) $8.5 \times 10^4$ b) $9 \times 10^{-4}$ c) $1.04 \times 10^{-6}$ d) $5.3 \times 10^7$