N is m% of what number?

Issof claims that the scale factor is 1/2. which statement about his claim is correct

Scrub a dub toothbrushes are $4.00 each. there is a 10% discount, but there is also a 6% sales tax after the discount is applied. what is the new price after tax? round to the nearest penny

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