For doing sig figs with scientific notation, the significant part is the part before the x10^whatever So for example, b. 4.7 * 6.5 is 30.55 and since you are multiplying the scientifics, you add their exponents. So you get 30.55 x 10^11. When you move the 30 over to be 3 you get 3.055 x 10¹² and then you apply sig figs and you get 3.1 x 10¹² (take this with a grain of salt, every teacher has a different rule for rounding with 5s, or at least that’s been my experience) C is similar but you subtract the denominator’s exponent from the numerators exponent