Perform the operation indicated. Write your answer in simplest form. \( \quad(-0.9)(0.4) \)

To solve the multiplication \( (-0.9)(0.4) \), you simply multiply the two numbers. First, ignore the signs and multiply \( 0.9 \) by \( 0.4 \): \[ 0.9 \times 0.4 = 0.36 \] Now, since one of the numbers is negative, the result will also be negative. So, \[ (-0.9)(0.4) = -0.36 \] Thus, the answer in its simplest form is \( -0.36 \).