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```1-4     ARMY AIR FORCES

d. Undoubtedly, some of the topics will seem elementary to many of the students. It must be remembered, however, that the mathematical proficiency demanded of an airman not only involves an understanding of the various operations, but also the ability to perform these operations accurately and quickly, and often under trying circumstances. Therefore, the time spent in practicing such a simple operation as addition, for example, will give valuable training, no matter how clearly the process is understood.

2. Materials, - In addition to pencil and paper, the student will need a ruler, a protractor, and a few sheets of graph paper.

SECTION II

FUNDAMENTAL OPERATIONS

Paragraph
Purpose and scope -----------------------------------------   3
Subtraction -----------------------------------------------   5
Multiplication --------------------------------------------   6
Division --------------------------------------------------   7
Conversion of decimals fractions to common fractions ------   8
Conversion of common fractions to decimals fractions ------   9
Addition and subtraction of fractions ---------------------  10
Multiplication of fractions--------------------------------------------11
Division of fractions-------------------------------------------------12
Ratio and proportion------------------------------------------------13
Positive and negative numbers----------------------------------------14
Addition of positive and negative numbers-------------------------------15
Subtraction of positive and negative numbers----------------------------16
Multiplication and division of positive and negative numbers------------17
Square root------------------------------------------------ 18
Miscellaneous exercises--------------------------------------19

3.Purpose and scope.-The purpose of this section is to provide a review of the four fundamental operations of arithmetic: addition, subtraction, multiplication, and division. Upon these fundamental operations all other mathematical calculations are based. One or more of them must be used in solving any problem.

4. Addition.-a. Addition is the operation of finding the sum of two or more numbers. To add several numbers, place the numbers in a vertical column so that the decimal points are all in a vertical line. (When no decimal point is indicated, it is assumed to be on the right.) Then add the figures in the right-hand column and place the sum under this column. If there is more than one figure in this sum, write down only the right-hand figure and carry the others to the next column to the left.

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