Explain how estimating you check the reasonableness of your answer

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

Which expression and diagram represent “renee biked four times as far this month as last month”?

Will give a: 122 b: 90 c: 48 d: 180