There's 2 ways you can do this:
1: multiply the numbers without the coefficients first. So 2.3 * 4.2 = 9.66
And 10^ -3 and 10^2. So, when you multiply numbers with coefficients, you add the exponents together. So -3 + 2 = -1. So 10^ -1
You can just write those 2 answers together as: 9.66 * 10^ -1
2: if you want to simplify this more, you would actually do the powers of 10 and multiply straight across. So 10^ -3 * 10^2 simplify to be 10^ -1. Which is the same as 1/10. You want to make 1/10 a decimal so you can multiply. 1/10 = 0.1. Then you just multiply the numbers. 2.3 * 0.1 * 4.2 = 0.966.
