Greg was adding two numbers on a number line. He started at 47 and added 26. He said the answer is 73. Is Greg's answer reasonable?
A. No, it is not reasonable because when you round the numbers to 40 and 20 the answer is 60. So the answer should be between 60 and 69.
B. No, it is not reasonable because when you round the numbers to 50 and 30, the answer is 80. So the answer to Greg's problem should be greater than 80.
C. Yes, it is reasonable because if you round the numbers to 45 and 25 the answer will be 70. So the answer to Greg's problem should be a bit more than 70.
