Centralia Junior High School
Centralia, Illinois
Math and Computers
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Number Sequences and LOGO


Arithmatic Sequence: A sequence of numbers in which the next number in the sequence can be obtained by adding or subtracting the same number.

Geometric Sequence: A sequence of numbers in which the next number in the sequence can be obtained by multiplying or dividing.


These LOGO procecures accompany pages 6-11 in the eighth grade math book. There are five procedures that illustrate how LOGO can be used to produce the patterns in the first five exercise on page 8. There is also a procedure to produce the fibonacci sequence on page 10.


Sequences on Page 8
Problem Logo Procedure Results
No. 9

5,7,9,11,...
to seq9 :n
if :n > 20 [stop]
pr :n
seq9 :n + 2 ; <-- arithmatic
end
? seq9 5
5
7
9
11
13
15
17
19
No. 10

95,91,87,83,...
to seq10 :n
if :n < 65 [stop]
pr :n
seq10 :n - 4 ; <-- arithmatic
end
? seq10 95
95
91
87
83
79
75
71
67
No. 11

2,8,32,128,...
to seq11 :n
if :n > 10000 [stop]
pr :n
seq11 :n * 4 ; <-- geometric
end
? seq11 2
2
8
32
128
512
2048
8192
No. 12

1,5,25,125,...
to seq12 :n
if :n > 20000 [stop]
pr :n
seq12 :n * 5 ; <-- geometric
end
? seq12 1
1
5
25
125
625
3125
15625
No. 13

1,4,9,16,...
to seq13 :n
if :n > 8 [stop]
pr :n * :n ; <-- neither arith. or geom.
seq13 :n + 1
end
? seq13 1
1
4
9
16
25
36
49
64
The Fibonacci Sequence, Page 10
Sequence Logo Procedure Results
1,1,2,3,5,8,13,... to fib :a :b
; The fibonacci Sequence
if :b > 1000 [stop]
pr :b
fib :b :a + :b
end
? fib 0 1
1
1
2
3
5
8
13
21
34
55
89
144
233
377
610
987

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