
Bradford T. answered 11/30/20
Retired Engineer / Upper level math instructor
The numbers in scientific notation are 2.3x105 and 6.7x104. To multiply, just multiply 2.3 and 6.7 as you would normally. 2.3x6.7 = 42.2. Then just add the exponents of 10 to get 109. So in scientific notation, the answer is 42.2x109 or 4.22x1010. In standard form, just move the decimal point 10 places to the right.
42,200,000,000
with commas added for clarity.