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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