Tito adds one more rock to his collection on the previous page. About how many rocks does he have now, rounded to the nearest ten? Rounded to the nearest hundred? Explain.
The correct answer and explanation is:
To provide the correct answer, let’s assume Tito had a specific number of rocks before he added one more. For this example, let’s assume Tito had 47 rocks before adding the extra one.
Rounded to the nearest ten:
First, you look at the ones digit. If it is 5 or greater, you round up. If it’s less than 5, you round down. In this case, Tito now has 48 rocks. The ones digit is 8, which is greater than 5, so you round up. The nearest ten to 48 is 50.
Rounded to the nearest hundred:
When rounding to the nearest hundred, you look at the tens digit. If it is 50 or greater, you round up, and if it’s less than 50, you round down. In this case, Tito has 48 rocks, and the nearest hundred is 0, since the tens place (4) is less than 50.
Explanation:
Rounding is the process of adjusting a number to make it simpler but still close in value to the original number. When rounding to the nearest ten, we focus on the ones digit. If that digit is 5 or higher, the tens digit increases by one, and the ones digit becomes zero. If the ones digit is less than 5, the tens digit stays the same, and the ones digit becomes zero.
Similarly, when rounding to the nearest hundred, we focus on the tens digit. If that digit is 5 or greater, the hundreds digit increases by one, and the tens and ones digits become zero. If the tens digit is less than 5, the hundreds digit stays the same, and both the tens and ones digits become zero.
In Tito’s case, after adding one more rock, rounding to the nearest ten gives 50, and rounding to the nearest hundred gives 0.