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MATHEMATICS FOR AIR CREW TRAINEES   5-6

Example: Subtract 765.328 from 843.1.
Solution:

843.100  EXTRA ZEROS
765.328
-------
 77.772 Answer
Figure 3.

d. A problem in subtraction may be checked by adding the answer to the number directly above it. The sum should always be the number in the top row.
(1) Example: Check the answer to the example in c(1) above.
Solution:
              843.100
         add  765.328
              -------     Check
               77.772
              -------
              843.100
             Figure 4.

(2) Units.- As in addition, care must be exercised to be sure that the units of the two quantities in a subtraction are the same.

 e. Exercises.- In each pf the following exercises subtract the smaller number from the larger. The symbol used to indicate subtraction is the minus sign (-). Therefore, an expression such as "1,205.789-980.833=?" means "What is the remained when 980.833 is subtracted from 1,205.789?" The number following the minus sign is always subtracted from the number preceding the sign.

(1) 1,205.789 in.-980.833 in.=?                      Answer.
(2) 19.52-.78=18.74
(3) 760,591-674,892=?
(4) 73.44 cu. in.-8.7375 cu. in.=64.7025 cu. in.     Answer. 
(5) 89.73-10.0045=?
(6) 941.7-87.372=854.328                             Answer.
(7) 1,004.78 miles-1,004.164 miles=?
(8) 100,433 sq. ft. - 99,857 sq. ft. = 576 sq. ft.   Answer.
(9) 1,000,000.3 - 998,757.4 = ?
(10) 3,756.04 - 2,489.7 = 1,266.34                   Answer.
 
6. Multiplication.-a. Multiplication is a short method of adding a number to itself as many times as may be indicated. The numbers multiplied together are called the factors and the result of the multiplication is called the product. To multiply two numbers together, or in other words, to find the product of two factors, first write

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