Explain how you decide where to place the decimal in 15.2

Hello, i need compare km^2 and km. what's difference in this?

Calculate the annual effective interest rate of a 12 % nominal annual interest rate compound monthly

Answer asap. you begin with 1/2 scoop of ice cream. since you're hungry, you ask the vendor for 2/7 more scoops of ice cream. then, you eat 5/8 scoops. how many scoops of ice cream are left on your cone? i will mark brainliest for first correct answer.