Whats 12.949 rounded to one decimal place

[Clarissaintheway]

........?

I mean 12.9 ha

Of course it's not 13. That would be rounded to the nearest whole number (or unit, as it used to be known). 1 decimal place is the tenths column, in this case the 9. You look to the column/number immediately to the right to determine whether to round up or down. If it's 4 or below, you round down, 5 or above you round up.

Surely it's 13?
12.949 3 places
12.95 2 places
13 1 place.

I would have thought

a) 13.0 (not 12.9) - 12.949 : round up to two places = 12.95, round up again - as the final figure is a 5, it increases the figure prior by 1 (5 and above - round UP), which brings the answer to 13.0 to one decimal place.

b) 3

c) 48

12.9, for 1 dp look between 12.9 and 13.0, 12.94....... is nearer to 12.9.

No, 1 decimal place is the first position after the decimal point.

Trust me: I teach this stuff to primary kids.

Oh my goodness. Some don’t understand rounding at all.

Think about it. If you’re rounding 12.949 to 1dp you’re finding whether it’s closer to 12.9 or 13.0. For it to be 13.9, the number would have to be 12.95 or bigger. Draw it out on a number line.

You only look at the digit on the right of the one you’re rounding to. Staring on the far right is utter nonsense.

Random No. You don't round, then round again, that way madness lies.

12.949 is 0.049 away from 12.9, and 0.051 away from 13.0
So when you round to 1dp it goes down to 12.9.

a) 13.0 (not 12.9) - 12.949 : round up to two places = 12.95, round up again - as the final figure is a 5, it increases the figure prior by 1 (5 and above - round UP), which brings the answer to 13.0 to one decimal place.

No, you don't consider any figure beyond the 12.94........ if you imagine it on a number line it's between 12.9 and 13.0 but it's less than half way, 12.95, so it's nearer to 12.9.

For 2 dp, look at the third and round that, anything after it doesn't matter etc..
For x dp, look at the x+1, that's all that matters.

Did the teacher not call out the answers for the children to mark each others' work? What did your DS says s/he said?

Though 3 and 48 are definitely correct, so maybe the other boy is deliberatley marking your DS's work down for some reason.

It might help if people who didn’t have a clue what they were talking about didn’t answer the op’s question as if they did.

13 (or 13.0) is a whole number, and has no decimal places at all, as the zero is not required.

I can't believe the number if function adults on here who can't round!

You don't go all the way to the last digit. It could go on for hundreds of digits. You just look at the digit directly to the right of the digit you are rounding to. There will be many many tutorial on YouTube, Best (and the others) please go an educate yourselves before you post again.

It might help if people who didn’t have a clue what they were talking about didn’t answer the op’s question as if they did.
Welcome to Mumsnet!!

I’d say 13.0

Does anyone really think anyone realises that they are totally misunderstanding primary level maths rather than honestly thinking 13 is the answer. Although the prevalence does understand why society needs a calculator for even the simplest of maths.

13 (or 13.0) is a whole number, and has no decimal places at all, as the zero is not required

This is incorrect. You’ve rounded it incorrectly. It’s also better to write it as 13.0 (if that were the answer) because the question has asked for a number with 1dp.

This thread is making me want to throw things.

*of functioning adults

I’d say 13.0

Wrong wrong wrong wrong wrong.

OhDear 13 (or 13.0) is a whole number, and has no decimal places at all, as the zero is not required.

Though interestingly, had the question been to round 12.959 to 1dp, I would personally give it as 13.0 to make clear the level of accuracy I had rounded to. I don't know what the 'official' rule is on this though.

12.9 - you only round from the number directly to the right.

Those of you with the pecualiar idea that you go all the way to the right and then work your way back, can one of you please round pi to one decimal place for me? I’ll wait...

Anything .5 or more gets rounded up to the next decimal place, anything .49 or below gets rounded down to zero. Time for you to speak to the teacher who set the work.

You’ve rounded it incorrectly.
What do you mean? The answer is 12.9, not 13. I haven't rounded it incorrectly at all. I was trying to explain what 1 decimal place means - possibly badly.