-      Let .04 x x = .000016. Then, x = .000016 .04 = .0016 4  = .0004

To solve this problem, we need to use the inverse operation of multiplication. In this case, we will be using division to solve the equation.

• Division is the inverse operation of multiplication, which means that whatever two numbers are multiplied together, they can be divided to get the original numbers back.
• The inverse operation can be used to solve equations where the unknown is multiplied by a known number.
• In this case, the equation is .04 x ? = .000016.
• To solve this equation, we need to divide both sides of the equation by .04, which will give us the answer.
• So, .04 divided by .04 is equal to 1.
• Now, we can divide .000016 by 1, which will give us .0004 as our answer.
• Therefore, the correct answer is Option A: 0.0004.

To summarise, .04 x ? = .000016 can be solved by using the inverse operation of multiplication, which is division. By dividing both sides of the equation by .04, we get the answer of .0004. Therefore, the correct answer is Option A: 0.0004.