Question

Evaluate the expression. Write your answer in scientific notation.(9×10^−3)+(2.4×10^−5) ÷ 0.0012The answer is 2.9 times 10^-2 I just don't know how to get that.

Answer 1

We are given this expression:

$(9*10^{-3})+(2.4*10^{-5})\div.0012$

Let's first evaluate 9 * 10^(-3) by moving the decimal place of 9 to the left 3 times.

$9*10^{-3}=.009$

Now, let's evaluate 2.4 * 10^(-5) by moving the decimal place of 2.4 to the left 5 times.

$.000024$

Now, we have this expression:

$.009+.000024\div.0012$

Start by dividing .000024 and .0012 because we must divide before adding.

Now, we have this expression:

$.009+.02$

Add these terms together to get:

$.029$

This number, .029 in scientific notation, is 2.9 * 10^(-2) since if we move the decimal place to the left in 2.9 two times, we get .029.