Section III. Rounding off numbers

r. Solve for x:

abc

rst

---- = ----

def

xyz

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s. Solve for b:

b+c=0

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Section III. ROUNDING OFF NUMBERS

1-15. DISCUSSION

Rounding off of numbers is the dropping of one or more digits of a number to

obtain the desired number of significant figures.

1-16. RULES

a. When the digit dropped is less than five, the last digit retained remains

unchanged; e.g., 6.582 becomes 6.58.

b. When the digit dropped is greater than five, the last digit retained is increased

by one (1); e.g., 6.586 becomes 6.59.

c. When the digit dropped is five alone or a five followed by only a zero or only

zeros, the digit remaining is rounded to the nearest even number; e.g., 2.585 becomes

2.58. Since the remaining digit was already an even number it was not changed.

However, the number 2.575 when rounded off becomes 2.58, since the remaining digit

was seven.

NOTE:

Although we will follow the above rule concerning the dropping of the number

five, be aware that it is not always observed. It is quite common to round up

if the digit dropped is five or greater and to leave the last digit unchanged if

the digit dropped is four or less.

1-17. EXERCISES, SECTION III

After you have completed these exercises, turn to the end of the lesson and

check your answers with the solutions.

MD0837

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