Round off Numbers – Part II

Here I wish to show you another way to teach the kids to do round off in math.

This method is to make use of a number line to round off a number. 

Example 1:

Round off 124 051 to the nearest tens.

(i)                            Look for the digit to be rounded off, which is 5

(ii)                          Find the digit just behind digit to be round off, which is 1.

(iii)                         Write down 124 050 on the left and add 1 to the digit to the round off, which is 124 060 on the right side.

 This has been shown in the picture below.

(iv)                       According to the number line digit 1 is nearer to “ 0 “, then we can conclude that 124 051 is nearer to 124 050.

Example 2:

Round off 124 051 to the nearest hundreds.

(i)                            Look for the digit to be rounded off, which is 0

(ii)                          Find the digit just behind digit to be round off, which is 5.

(iii)                         Write down 124 000 on the left and add 1 to the digit to the round off, which is 124 100 on the right side.

(iv)                       According to the number line digit 5 is nearer to “ 10 “, then we can conclude that 124 051 is nearer to 124 100.

Example 3:

Round off 124 051 to the nearest thousands.

(i)                            Look for the digit to be rounded off, which is 4.

(ii)                          Find the digit just behind digit to be round off, which is 0.

(iii)                         Write down 124 000 on the left and add 1 to the digit to the round off, which is 125 000 on the right side.

(iv)                       According to the number line digit 0 is nearer to “ 0 “, then we can conclude that 124 051 is nearer to 124 000.

Example 4:

Round off 128 051 to the nearest ten thousands.

 (i)                            Look for the digit to be rounded off, which is 2.

(ii)                          Find the digit just behind digit to be round off, which is 8.

(iii)                         Write down 120 000 on the left and add 1 to the digit to the round off, which is 130 000 on the right side.

(iv)                       According to the number line digit 0 is nearer to “ 0 “, then we can conclude that 128 051 is nearer to 124 000.

Example 5:

Round off 328 051 to the nearest ten thousands.

 (i)                            Look for the digit to be rounded off, which is 3.

(ii)                          Find the digit just behind digit to be round off, which is 2.

(iii)                         Write down 3000 000 on the left and add 1 to the digit to the round off, which is 400 000 on the right side.

(iv)                       According to the number line digit 0 is nearer to “ 0 “, then we can conclude that 328 051 is nearer to 300 000.

Now, I hope these few tips will help kids to have better understanding on how to do rounding off in math.

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