12. Multiply twonty thousand by thirty thousand, and write the product in scientific notation.

To multiply twenty thousand (20,000) by thirty thousand (30,000), we begin by expressing them in scientific notation: 20,000 = 2.0 x 10^4 and 30,000 = 3.0 x 10^4. Now, multiplying the coefficients: 2.0 x 3.0 = 6.0 and adding the exponents: 10^4 x 10^4 = 10^(4+4) = 10^8. So, the product is 6.0 x 10^8 when expressed in scientific notation. An easy way to remember scientific notation is to think of it as a more readable way of handling really big (or really small) numbers! It's especially useful in fields like chemistry and physics, where such numbers often come into play. Just keep multiplying the coefficients and adding the exponents — simple as pie! Don’t forget a little practice can really help solidify these concepts. Consider making flashcards with different numbers converted to scientific notation or practice multiplying various numbers in scientific notation. It can turn into a fun game while reinforcing your skills! Plus, challenging a friend to see who can solve more in a set time can make it even more engaging.