Rounding Rounding &&

MathLineMathLine

Rounding

Rounding is also referred Rounding is also referred to as estimatingto as estimating

Rounding

MathLine offers a very effective way to build a MathLine offers a very effective way to build a concrete picture of roundingconcrete picture of rounding

Rounding

Rounding is challenging for many students Rounding is challenging for many students

while connecting tactile objects while connecting tactile objects to abstract numbers. to abstract numbers.

Round 67 to the nearest 10Round 67 to the nearest 10

Rounding

Rounding

Either round down to 60 Either round down to 60

60 7067

or round up to 70or round up to 70

Rounding

60

There are 3 questions to determine There are 3 questions to determine which ten is correct.which ten is correct.

67 70

Rounding

60 67

1) To which ten is 67 closer?1) To which ten is 67 closer?

70

Is 67 closer to 70?Is 67 closer to 70?

Rounding

60 67

or is 67 closer to 60?or is 67 closer to 60?

70

Rounding

60 67

67 is closer to 70! 67 is closer to 70!

70

Rounding

60

2)2) How many rings is 67 away from 70?How many rings is 67 away from 70?

67 70

33

Rounding

60

77

2)2) How many rings is 67 away from 60?How many rings is 67 away from 60?

67 70

33

Rounding

60

77

67 is only 3 rings away from 70,67 is only 3 rings away from 70,but 7 rings away from 60but 7 rings away from 60

67 70

33

Rounding

60

The blue ring is The blue ring is the middle between 60 and 70.the middle between 60 and 70.

67 70

3) What side of the blue ring does 67 3) What side of the blue ring does 67 appear?appear?

Rounding

60

High sideHigh side

67 70

Rounding

60

Or Low sideOr Low side

67 70

Rounding

60

67 is on the high side67 is on the high side

67 70

Rounding

60 67

……round to 70round to 70 Therefore when rounding 67 Therefore when rounding 67

to the nearest 10…to the nearest 10…

70