What is the greatest number that will produce 1220 when rounded off to the nearest tens?
The correct answer and explanation is:
The greatest number that will produce 1220 when rounded to the nearest ten is 1224.
Here’s how rounding works for numbers to the nearest ten: you look at the digit in the ones place (the last digit). If this digit is 5 or greater, the number is rounded up to the next ten. If the digit is less than 5, the number is rounded down to the nearest lower ten.
To understand why 1224 is the correct answer, let’s break it down:
- The number 1220 is rounded to the nearest ten, so the number must fall within a range that rounds to 1220.
- The range for numbers rounding to 1220 is from 1215 to 1224.
- If the number is 1215 or greater, it rounds up to 1220, and if it’s 1225 or greater, it rounds up to 1230.
Now, consider 1224:
- The digit in the ones place is 4, which is less than 5.
- Therefore, 1224 rounds down to 1220 when rounded to the nearest ten.
If the number were 1225 or greater, it would round to 1230. Thus, 1224 is the greatest number that rounds to 1220, because any higher number would round to 1230.
This explanation shows the importance of the digit in the ones place when rounding numbers to the nearest ten. The key here is knowing that numbers from 1215 to 1224 will all round to 1220.