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Unformatted text preview: rm: Now you have the single digit 3 to the left of the decimal in the denominator.
Step 4: Focus only on the whole number parts of the
numerator and denominator and solve. 15.30794
3.14900 15
=5
3 An approximate answer to this complex division problem is 5. If this answer is not precise
enough, keep one more decimal place and do long division (eg., 153 31 4.9). * Manhattan GMAT Prep
the new standard 17 Chapter 1 DIGITS & DECIMALS STRATEGY Decimal Operations
ADDITION AND SUBTRACTION
To add or subtract decimals, make sure to line up the decimal points. Then add zeroes to
make the right sides of the decimals the same length.
4.319 + 221.8
Line up the
decimal points
and add zeroes. 10 − 0.063
4.319
+ 221.800
226.119 Line up the
decimal points
and add zeroes. 10.000
− 0.063
9.937 Addition & Subtraction: Line up the decimal points!
The rules for decimal
operations are different
for each operation. MULTIPLICATION
To multiply decimals, ignore the decimal point until the end. Just multiply the numbers as
you would if they were whole numbers. Then count the total number of digits to the right
of the decimal point in the factors. The product should have the same number of digits to
the right of the decimal point.
0.02 × 1.4 Multiply normally: 14
×2
28 There are 3 digits to the right of the decimal point in the factors (0 and 2 in the first factor
and 4 in the second factor). Therefore, move the decimal point 3 places to the left in the
product: 28 → 0.028.
Multiplication: In the factors, count all the digits to the right of the decimal point—
then put that many digits to the right of the decimal point in the product.
If the product ends with 0, count it in this process: 0.8 × 0.5 = 0.40, since 8 × 5 = 40.
If you are multiplying a very large number and a very small number, the following trick
works to simplify the calculation: move the decimals in the opposite direction the same
number of places.
0.0003 × 40,000 = ?
Move the decimal point RIGHT four places on the 0.0003 → 3...
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 Spring '07
 MEJIAS

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