Study the table carefully.
- How many dots are there in Figure 20?
- If there are 41 dots, what Is the Figure number?
(a)
Pattern for the number of dots
Figure 1: (1 - 1) x 5 + 1 = 1
Figure 2: (2 - 1) x 5 + 1 = 6
Figure 3: (3 - 1) x 5 + 1 = 11
Figure 4: (4 - 1) x 5 + 1 = 16
Formula:
Number of dots = (Figure number - 1) x 5 + 1
Number of dots in Figure 20
= (20 - 1) x 5 + 1
= 96
(b)
Figure number for 41 dots
(Figure number - 1) x 5 + 1 = 41
(Figure number - 1) x 5 = 41 - 1 = 40
(Figure number - 1) = 40 ÷ 5 = 8
Figure number = 8 + 1 = 9
Answer(s): (a) 96; (b) 9