Question

Which expression is equivalent to
(12 x 10^4)(6 x 10^5) ?
A. 7.2 x 10^10
B. 72 x 10^9
C. 7.2 x 10^-1
D. 7.2 x 10^2

Answer 1

To multiply numbers written in scientific notation, you can simply multiply the coefficients and add the exponents.

The coefficient of the first number is 12 and the exponent is 4.
The coefficient of the second number is 6 and the exponent is 5.

Multiplying the coefficients gives: 12 x 6 = 72.
Adding the exponents gives: 4 + 5 = 9.

Therefore, the expression is equivalent to 72 x 10^9.

The correct answer is B. 72 x 10^9.