Blank x 0.4 = 0.2 equals?

In simplified exponential notation, the expression a^2•a^-3•a 1/a 0

Adaycare center charges a $75 enrollment fee plus $100 per week. which of the following represents the cost of sending a child to daycare for 14 weeks?

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed