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Lesson 1: Rounding to nearest 10 or 100

# Rounding to the nearest 10 on the number line

Round numbers to the nearest ten using a number line.

## Want to join the conversation?

• How would you go about explaining and rounding a number like 120 to the nearest 10?
• 120 itself is a multiple of 10

[0,10,20,30,40,50,60,70,80,90,100,110,120]

So, 120 "rounded to nearest 10" would still be 120
• I think I might have spotted a mistake in one of the pratice test questions. Here's the question:

Which number line highlights all whole numbers that round to 200 if we are rounding to the nearest hundred?

A) 150 and 240
B) 200 and 299
C) 150 and 249

The problem is that option A is considered INCORRECT. Shouldn't BOTH options A and C be correct? And actually, isn't 240 even closer to 200? Or am I doing something wrong?
• "C" is the correct value. The problem asked for all whole numbers that would round to 200. Option "A" does not have all the values. Only option C has all the numbers.
• Can the number infinity be rounded
• Infinity is regarded as a concept rather than an actual number. "Infinity is that which is boundless, endless, or larger than any natural number." [1]

Rounding is a math operation that involves approximating an actual number to a specific level of precision. However since infinity is not a finite number, rounding cannot be used in this context as the same way that finite numbers can be.

[1] https://en.wikipedia.org/wiki/Infinity
• Is it means (at ) that 3 is rounded to zero if we round it to the ten's place? What is the practical meaning to do that? :O
• When rounding numbers, anything that is 0-4 will be rounded down, whereas anything 5-9 will be rounded up. When he says that 3 is rounded to 0, that means that any number with a 3 in the one's place will be rounded down to the nearest 10. 13 gets rounded to 10. 53 gets rounded to 50. 583 gets rounded to 580.
• what would the number 10 be rounded to ?
• 10 would stay at 10 when rounded to the nearest 10.
• Can anything be rounded?
• You can round every number, but depending on what you're rounding to, the number might not change. Take the number 60, for example. If we're rounding to the nearest 100, it will become 100. If we're rounding to the nearest 10, it will remain 60.
• like what if you had to round 20 or 50 or any 2 digit number with a 0 in the 1s place
• The number wouldn't change. Any number with a 0 in the one's place is a multiple of ten, therefore the nearest 10 is itself.
• whats 2500 rounded through the nearest 1000
• 3000. You can cancel out the zeros for now. That will be 25 rounded to the nearest 10. Since 25 has a five at the end, then you round it up into 30. You add the zeros back and it becomes 3000.