Question

Which answer is the most reasonable estimation? Mike is driving a total of 100 miles. He drove 23 miles before stopping at a gas station. Then he drove 58 more miles before stopping for lunch. About how much farther does Mike have to drive? A. about 20 miles B. about 80 miles C. about 10 miles D. about 70 miles

Answer 1

the answer is A because if you subtract 100-23-58 you get 19 then you simplify it

Answer 2

23 rounds to 20.
58 rounds to 60.

You then take your rounded numbers, 60 + 20 = 80. So, Mike has driven ABOUT 80 miles so far. 

Now you take his estimated distance & subtract it from the 100. Your answer is 20. So, your answer is A) 20 miles.

To check your work, you could add 23 + 58 = 81. You then subtract 100 - 81 = 19. 19 rounds to 20, which is your answer.

I hope this helps & you understand ! (: