Math Problem Solving Strategies
The following are some examples of problem solving strategies.
Explore it//Act it/Try it (EAT) method (Basic)
Explore it//Act it/Try it (EAT) method (Intermediate)
Explore it//Act it/Try it (EAT) method (Advanced)
Finding a Pattern (Basic)
Finding a Pattern (Intermediate)
Finding a Pattern (Advanced)
Find A Pattern (Intermediate)
In this lesson, we will look at some intermediate examples of Find a Pattern method of problem solving strategy.
Example:
The figure shows a series of rectangles where each rectangle is bounded by 10 dots
a) How many dots are required for 7 rectangles?
b) If the figure has 73 dots, how many rectangles would there be?

Solution:
Rectangles |
Pattern |
Total dots |
1 |
10 |
10 |
2 |
10 + 7 |
17 |
3 |
10 + 14 |
24 |
4 |
10 + 21 |
31 |
5 |
10 + 28 |
38 |
6 |
10 + 35 |
45 |
7 |
10 + 42 |
52 |
8 |
10 + 49 |
59 |
9 |
10 + 56 |
66 |
10 |
10 + 63 |
73 |
a) The number of dots required for 7 rectangles is 52.
b) If the figure has 73 dots, there would be 10 rectangles.
Example:
Each triangle in the figure below has 3 dots. Study the pattern and find the number of dots for 7 layers of triangles.

Solution:
Layers |
Pattern |
Total dots |
1 |
3 |
3 |
2 |
3 + 3 |
6 |
3 |
3 + 3 + 4 |
10 |
4 |
3 + 3 + 4 + 5 |
15 |
5 |
3 + 3 + 4 + 5 + 6 |
21 |
6 |
3 + 3 + 4 + 5 + 6 + 7 |
28 |
7 |
3 + 3 + 4 + 5 + 6 + 7 + 8 |
36 |
The number of dots for 7 layers of triangles is 36.
Example:
The table below shows numbers placed into groups I, II, III, IV, V and VI. In which groups would the following numbers belong?
a) 25
b) 46
c) 269
I |
1 |
7 |
13 |
19 |
25 |
II |
2 |
8 |
14 |
20 |
26 |
III |
3 |
9 |
15 |
21 |
27 |
IV |
4 |
10 |
16 |
22 |
|
V |
5 |
11 |
17 |
23 |
|
VI |
6 |
12 |
18 |
24 |
|
Solution:
The pattern is: The remainder when the number is divided by 6 determines the group.
a) 25 ÷ 6 = 4 remainder 1 (Group I)
b) 46 ÷ 6 = 7 remainder 4 (Group IV)
c) 269 ÷ 6 = 44 remainder 5 (Group V)
Example:
The following figures were formed using matchsticks.

a) Based on the above series of figures, complete the table below.
Number of squares |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
Number of triangles |
4 |
6 |
8 |
10 |
|
|
|
|
Number of matchsticks |
12 |
19 |
26 |
33 |
|
|
|
|
b) How many triangles are there if the figure in the series has 9 squares?
c) How many matchsticks would be used in the figure in the series with 11 squares?
Solution:
a)
Number of squares |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
Number of triangles |
4 |
6 |
8 |
10 |
12 |
14 |
16 |
18 |
Number of matchsticks |
12 |
19 |
26 |
33 |
40 |
47 |
54 |
61 |
b) The pattern is +2 for each additional square.
18 + 2 = 20
If the figure in the series has 9 squares, there would be 20 triangles.
c) The pattern is + 7 for each additional square
61 + (3 x 7) = 82
If the figure in the series has 11 squares, there would be 82 matchsticks
Example:
Seven ex-schoolmates had a gathering. Each one of them shook hands with all others once. How many handshakes were there?
Solution;
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A |
B |
C |
D |
E |
F |
G |
A |
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B |
● |
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C |
● |
● |
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D |
● |
● |
● |
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E |
● |
● |
● |
● |
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F |
● |
● |
● |
● |
● |
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G |
● |
● |
● |
● |
● |
● |
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HS |
6 |
5 |
4 |
3 |
2 |
1 |
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Total = 6 + 5 + 4 + 3 + 2 + 1 = 21 handshakes
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