Estimate 330,000,000,000,000,000,000,000 kg using one digit whole number times a power of 10 including units

Name the most appropriate metric unit for each measurement like the mass of cow

For one history test, keith had to answer 40 questions. of these 40 questions, keith answered 28 of them correctly. what percent did keith get on his history test? round your answer to the nearest tenth if necessary

Which expression is equivalent to -5(3x - 6/7)