1.02  Order of Operations

 from Basic Algebra: One Step at a Time © 2002

P. 7-12

Dr. Robert J. Rapalje

Seminole State College of Florida

 

ANSWERS TO ALL EXERCISES ARE INCLUDED AT THE END OF THIS PAGE

 

To see selected solutions in Living C O L O R  click here!

 

In the first section, different number systems were defined, and symbols relating to addition (subtraction) and multiplication (division) of numbers within those systems were identified.  In order to execute these basic operations it is necessary to establish a few traditions (agreements!) as to how these operations will be carried out.  The signs of the numbers must also be addressed.  In this section it is preferred that you use the calculator “in your head.”  In the next section, you will be encouraged to use the calculator “in your hand.”  If you do not already have one, be looking for a good sale on inexpensive calculators!

 ORDER OF OPERATIONS

In your head, perform the following calculations:

1.  4 + 6 ·  2 = _______                                 2.  16 ÷ 8 · 2 = _______

 3.   5 · 2 2  = _______                                   4.   (3 + 4) 2 = _______

 Solutions:

 1.        If addition is performed first, the answer is 20.

            If multiplication is performed first, the answer is 16.

 2.        If division is performed first, the answer is 4.

            If multiplication is performed first, the answer is 1.

 3.        If multiplication is performed first, the answer is 100.

            If the power is performed first, the answer is 20.

 4.        If you add first, the answer is 49. 

            If you square the 3 and then square the 4 (which the problem does not say to do!),

            then the answer would be 25.

           (SEE NEXT PARAGRAPH!! )

A mathematics system must have unique solutions to basic operations such as these.  In order to perform these operations and  always arrive at the same conclusion, we must agree to certain traditions which are called the order of operations agreement.  This agreement is generally accepted across the world and in most arenas of life.  If you obey these traditions, you will obtain consistent results in agreement with everyone else.          

ORDER OF OPERATIONS

LEVEL 1:     Simplify within symbols of grouping:    

                      Parentheses (  ), brackets [ ],  set braces { }, above or below 

                      fraction bars,  and absolute value bars |  | (see next section).

LEVEL 2:     Raise to the power (i.e. exponents).

LEVEL 3:     Multiply or divide in order from left to right.

LEVEL 4:     Add or subtract in order from left to right.

 Now, we can say of the examples on the previous page, the “correct answers” are:

1.  16;                 2.  4;                 3.  20;                  4.  49.

 

EXERCISES:             Simplify each of the following according to the order of operations agreement.

 1.  2 + 8 · 4                              2.  20 ÷ 4 · 5                                      3.  2 · 5 2 

 = __________                             = __________                                   = __________        

 = __________                             = __________                                   = __________

 4.  32 ÷ 4 · 8                            5.  100 ÷ 5 2                                        6.   (2 · 5) 2 

 = __________                             = __________                                    = __________

 = __________                             = __________                                    = __________

  7.   12 + 8 ÷ 2                            8.  12 ÷ (3 + 3)                                  9.   5 + 9 ·  2 

   = __________                              = __________                                  = __________         

   = __________                              = __________                                 = __________  

10.  (100 ÷ 5) 2                         11.  12 ÷ 3 + 3                                   12.  (5 + 9) · 2  

   = __________                              = __________                                  = __________         

   = __________                              = __________                                  = __________  

13.   20 - 5 · 0                           14.  12 + 3 ÷ 3                                    15.  12 ÷ (3 ÷ 3)

    = __________                              = __________                                   = __________    

   = __________                              = __________                                   = ___________ 

16.    5 + 5 2                                 17.  (12 + 3) ÷ 3                                18.  18 + 2 · 0 

    = __________                                = __________                                  = __________     

   = __________                                = __________                                  = __________

19.  12 - 8 ÷ 2                                20.  12 ÷ (3  · 2)                              21.  12 ÷ 3 · 2 

    = __________                                  = __________                                 = __________        

   = __________                                  = __________                                 = __________  

22.  (12 - 8) ÷ 2                              23.  (12 - 8)2 ÷ 2                               24.   20 - (8 ÷ 2) 2 

   = __________                                  = __________                                   = __________      

   = __________                                  = __________                                   = __________

 25.  (12 - 8 ÷ 2) 2                             26.   (12 - 8) ÷ 22                             27.  20 + (8 ÷ 2) 2  

    = __________                                    = __________                                 = __________    

   = __________                                    = __________                                 = __________

 28.   5 ·  5 2                                       29.   ( 5 ·  5) 2                                30.  18 ÷ 2 ·  3 

    = __________                                     = __________                                 = __________      

   = __________                                     = __________                                 = __________

 31.   8 + 3 · 2 2                                          32.   5 · 3 2 + 11 - 2 2  

    = _______________                                    = _______________

   = _______________                                    = _______________

   = _______________                                    = _______________               

33.   24 - 3 ·  4 + 6 ÷ 2                               34.   12 + 18 ÷ 3 2 + 6

     = _______________                                   = _______________         

     = _______________                                   = _______________  

     = _______________                                   = _______________       

35.   12 + (18 ÷ 3)2 + 6                               36.   6 + 6 2 ÷ 3 · 2

      = _______________                                  = _______________     

     = _______________                                  = _______________

      = _______________                                  = _______________      

                                                                         = _______________

37.  (16 + 22 ) ÷ 2 · 2                                 38.  8 + 2 ·  3 2 - 5

     = _______________                                    = _______________

     = _______________                                    = _______________

     = _______________                                   = _______________      

     = _______________                                   = _______________

39.   52 + 42 ÷ 22 + 32                                  40.  (16 + 22 ) ÷ (2 + 2)

     = _______________                                   = _______________   

     = _______________                                   = _______________

     = _______________                                   = _______________        

     = _______________                                   = _______________

 

EXTRA CHALLENGE:

41.    3·42 + 7 - 2·32 ÷ 6 + 3·52                           42.   24 - 12 ÷ 2·3 + 6·23

 

 

 

 

43.    (5 · 2)2 - 20 ÷ 2 · (8 - 3) + 10 - 3 + 7            44.    35 - 20 ÷ 5 + 72 · 2 - 6 · 3 + 9 + 10 ÷ 2

 

 

 

 

45.                                              46.    

 

 

 

 

47.                     48.  

 

 

 

 

ANSWERS 1.02 

p. 8 - 12:         1. 34; 2. 25; 3. 50; 4. 64; 5. 4; 6. 100; 7. 16; 8. 2;   9. 23;  10. 400;  11. 7;  12. 28;  13. 20;  14. 13; 15. 12; 16. 30; 17. 5; 18. 18; 19. 8; 20. 2; 21. 8; 22. 2; 23. 8; 24. 4; 25. 64; 26. 1; 27. 36; 28. 125; 29. 625; 30. 27; 31. 20; 32. 52;  33. 15;  34. 20;   35. 54;  36. 30;  37. 20;  38. 21; 39. 38; 40. 5; 41. 127; 42. 54; 43. 64; 44. 125; 45. 2; 46. 1; 47. 5; 48. 4.

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Dr. Robert J. Rapalje Altamonte Springs Campus
Contact me at:   rapaljer@seminolestate.edu
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