Rounding to 2 Decimal Places

Answers

Nid 953.90 Glum 43.65 Drat 9.56 Lush 9.34 Brum 0.81

Oz 3.36 Plonk 6.65 Reem 0.83 Slythy 0.57 Welly-wang 0.60

1029.27

Would you have got the same answer if you had added all of the original numbers together then rounded off the answer?

Note to teacher: Doing this activity once with a class helps students develop strategies. It is only when they do this activity a second time that they will have the opportunity to practise those strategies. That is when the learning is consolidated. Click the button above to regenerate another version of this starter from random numbers.

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Extension

Do you know how to round negative numbers? If values exactly half way between get rounded up should -37.25 be rounded to -37.2 or -37.3? Does ‘rounded up’ mean rounded to the larger value or the value furthest away from zero?

A system of rounding commonly used in bookkeeping and some computing procedures is called ‘round half to even’. In this system half way values are rounded either up or down in order to make the last digit an even number.

So, for example, 37.25 becomes 37.2, 37.15 also becomes 37.2 and −37.25 becomes −37.2 without any doubt.

This method of rounding is also useful when rounding values in large data sets as it evens out the rounding ups and rounding downs for the half way values.

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	Teacher, do your students have access to computers such as tablets, iPads or Laptops?  This page was really designed for projection on a whiteboard but if you really want the students to have access to it here is a concise URL for a version of this page without the comments: Transum.org/go/?Start=June20 However it would be better to assign one of the student interactive activities below.

Here is the URL which will take them to a related student activity.

Transum.org/go/?to=roundingsnap

 

Curriculum Reference

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