So this is asking me to order the numbers from least to the greatest can anybody please help me???

What is the number 321,000,000 in scientific notation? also what is the number? ?

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

0if x and y vary inversely and y=6 as x=7, what is the constant of variation?