GMAT Official Guide Quantitative Review 2019_ Book

3.1• , , Arithmetic

Multiplication of decimals.

To multiply decimals, multiply the numbers as if they were whole numbers and then insert the decimal

point in the product so that the number of digits to the right of the decimal point is equal to the sum

of the numbers of digits to the right of the decimal points in the numbers being multiplied. For

example:

2.09 (2 dig江sto the right)

x 1.3 (1 digit to the right)

627

2090

2.717 (2+ 1 = 3 digits to the right)

Division of decimals.

To divide a number (the dividend) by a decimal (the divisor), move the decimal point of the divisor to

the right until the divisor is a whole number. Then move the decimal point of the dividend the same

number of places to the right, and divide as you would by a whole number. The decimal point in the

quotient will be directly above the decimal point in the new dividend. For example, to divide 698.12

by 12.4:

will be replaced by:

12.4严

124 三

and the division would proceed as follows:

4. Real Numbers

56.3

124 质

型

781

744

372

立

。

Ali real numbers correspond to points on the number line and all points on the number line correspond

to real numbers. All real numbers except zero are either positive or negative.

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