Estimate the answer (3851)(40308*10^-12) all over (.0019*10^14)(.000039)

Answer 1

Best way to estimate is to convert all terms into one-digit multiples of powers of 10. Then use rules of exponents to do the multiplication and division.

3851 ≅ 4 x 10³

40308 x 10^-12 ≅ 4 x 10^-8

0.0019 x 10¹⁴ ≅ 2 x 10¹¹

0.000039 ≅ 4 x 10^-5

(4 x 10³)(4 x 10^-8) = 16 x 10^-5

(2 x 10¹¹)(4 x 10^-5) = 8 x 10⁶

(16 x 10^-5)/(8 x 10⁶) = 2 x 10^-11