Question 1: Round to the nearest 10 to find an estimate.
To round 748 to the nearest 10, we look at the digit in the ones place, which is 8. Since 8 is 5 or greater, we round up. Therefore, 748 rounds to 750.
For 431, the digit in the ones place is 1. Since 1 is less than 5, we round down. Therefore, 431 rounds to 430.
Now we can perform the estimated subtraction: 750 - 430 = 320.
So, the estimate for 748 - 431, when rounded to the nearest 10, is 320.
Question 2: Round to the nearest 100 to find an estimate.
To round 748 to the nearest 100, we look at the digit in the tens place, which is 4. Since 4 is less than 5, we round down. Therefore, 748 rounds to 700.
For 431, the digit in the tens place is 3. Since 3 is less than 5, we round down as well. Therefore, 431 rounds to 400.
Now we can perform the estimated subtraction: 700 - 400 = 300.
So, the estimate for 748 - 431, when rounded to the nearest 100, is 300.
Question 3: Does rounding to the nearest 10 or the nearest 100 give a closer estimate of 748 - 431?
Rounding to the nearest 10 gives an estimate of 320, while rounding to the nearest 100 gives an estimate of 300. To determine which estimate is closer to the actual result of 748 - 431, we first calculate the actual value:
748 - 431 = 317.
Now we can compare:
- The estimate rounding to the nearest 10 is 320, which is 3 more than the actual value (317).
- The estimate rounding to the nearest 100 is 300, which is 17 less than the actual value.
Since 320 is closer to 317 than 300 is, rounding to the nearest 10 gives a closer estimate of the actual subtraction than rounding to the nearest 100.
2 answers