Rounding the numbers to nearest 50?

(9 Posts)
irvineoneohone Sun 29-May-16 07:45:02

Please help, there are questions like this.

Estimate the answer to 4243 + 1734 by rounding the numbers to:
the nearest 1000 (4000 + 2000)
the nearest 100 (4200 + 1700)
the nearest 50
the nearest 10 (4240 + 1730)

How do you do the nearest 50? I haven't got a clue!

Mirandawest Sun 29-May-16 07:47:17

In your example that would be

4250+ 1750

I'd round up if ended in 25 or greater and round down if ended in 24 or less.

BeauGlacons Sun 29-May-16 07:49:18

Can you not follow the logo in the examples that have been given.

Is 50 closer to moving up or moving down.

BeauGlacons Sun 29-May-16 07:49:56

Logic op

ExtremelyConfidential Sun 29-May-16 07:50:45

4250 + 1750

Go to closest unit of 50. Greater than or equal to 25= go up, else go down

Bit of a silly question given its easier to do the actual calculation since no line adds up to over 10 so no carry overs to get muddled.

RafaIsTheKingOfClay Sun 29-May-16 07:53:47

The same way that you'd round to the nearest hundred or thousand or whole number.

Round the number to the closest multiple of 50. Is 4243 closer to 4200 or 4250? Then do the same for 1734.

irvineoneohone Sun 29-May-16 07:59:07

Thank you every one. Especially Rafa, it makes sense now, after reading your explanation.

RafaIsTheKingOfClay Sun 29-May-16 08:06:27

It will help if your DS knows that mutiples of 50 will end in 00 or 50. He'll need to be able to work out which two multiples the numbers fall between.

irvineoneohone Sun 29-May-16 17:37:44

Thank you again, Rafa. Question like this make me realise that ds maybe good at some maths, but he really needs deeper understanding of concepts, so he can apply it to something he never been asked to do before.
Seems like all those mastery and deepening in new NC is actually good for children like my ds, rather than just going forward with shallow understanding.

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