Answer:
7070
Explanation:
First, read the problem carefully.
The problem states: "so that it has only 1 nonzero digit."
This means that all the digits in the number should be zero except for one digit. The given numbers are 6988 and 67.
How do you round numbers?
If you are round to the hundreds place, look at the digit before, which is the digit in the tens place. Same if you are rounding to the thousands digit or tens digit; just look at the digit before.
How to look?
For example, if you are rounding to the nearest ten, look at your ones digit. If the ones digit is any of the numbers from 0 to 4, round down. In this case, rounding down means you keep the tens digit the same and change the digit following it into 0.
Ex.
1. Round 42 to the nearest ten.
2 is a number from 0 to 4, so we round down.
This yields an answer of 40.
2. Round 74 to the nearest ten.
4 is between 0 and 4, so we round down.
74 rounded to the nearest ten is 70.
Next, if the number following the digit you are rounding to is between 5 and 9, round up. Rounding up is taking the digit and bumping it up by 1.
Ex.
1. Round 151 to the nearest hundred.
We are rounding to the nearest hundred so we look to the digit behind it, the tens digit. The tens digit it between 5 and 9, so we round up, or add one to the hundreds digit. This results in an answer of 200. (151 --> 200)
How do we do this problem then?
Rounding 6988 so that it only has 1 nonzero digit means it goes up to 7000. Rounding 67 up gives us 70.
Finally, we add 7000 + 70 = 7070