Sun-Yi estimated 270 + 146 and got 300 is her estimate reasonable.
270 rounds up to 300
146 rounds down to 100
so one estimate is 400
270+150 = 420
So 300 is not very close
To determine if Sun-Yi's estimate of 300 is reasonable for the sum of 270 and 146, you can calculate the actual sum and compare it to her estimate.
To find the actual sum, you add the two numbers together:
270 + 146 = 416
Now, compare the actual sum (416) to Sun-Yi's estimate (300). You can see that her estimate is lower than the actual sum.
Therefore, Sun-Yi's estimate of 300 is not reasonable because it is lower than the actual sum, 416.